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 Timezone: CET
Creation date: 20230203
Creation time: 232902
 Number of references
182
article
SotoValle2022
Vortex identification methods applied to wind turbine tip vortices
eawe, Wind Energ. Sci.,
2022
3
15
7
585 – 602
This study describes the impact of postprocessing methods on the calculated parameters of tip vortices of a wind turbine model when tested using particle image velocimetry (PIV). Several vortex identification methods and differentiation schemes are compared. The chosen methods are based on two components of the velocity field and their derivatives. They are applied to each instantaneous velocity field from the dataset and also to the calculated average velocity field. The methodologies are compared through the vortex center location, vortex core radius and jittering zone. Results show that the tip vortex center locations and radius have good comparability and can vary only a few grid spacings between methods. Conversely, the convection velocity and the jittering surface, defined as the area where the instantaneous vortex centers are located, vary between identification methods. Overall, the examined parameters depend significantly on the postprocessing method and selected vortex identification criteria. Therefore, this study proves that the selection of the most suitable postprocessing methods of PIV data is pivotal to ensure robust results.
https://doi.org/10.5194/wes75852022
R.SotoValle
S.Cioni
S.Bartholomay
M.Manolesos
C. N.Nayeri
A.Bianchini
C. O.Paschereit
article
Gilotte2022
Aerodynamical characteristics of a reduced scale ground vehicle according to yaw angle variations
International Journal of Numerical Methods for Heat & Fluid Flow
2022
32
4
12221236
The purpose of this paper is to study pressure measurement correlations, as the location of the pressure sensors should enable to capture variation of the drag force depending on the yaw angle and some geometrical modifications. The present aerodynamical study, performed on a reduced scale mockup representing a sport utility vehicle, involves both numerical and experimental investigations. Experiments performed in a wind tunnel facility deal with drag and pressure measurements related to the side wind variation. The pressure sensor locations are deduced from wall streamlines computed from large After validation of the drag coefficient (Cd) values computed with an aerodynamic balance, measurements should only imply pressure tap mounted on the vehicle to perform real driving emission (RDE) tests. Relation presented in this paper between pressure coefficients measured on a side sensor and the drag coefficient data must enable to better quantify the drag force contribution of a ground vehicle in RDE tests.
https://www.emerald.com/insight/09615539.htm
Keywords Crosscorrelation, Drag reduction, Ground vehicle, Real driving emissions test,Wind tunnel measurements, Yaw angle variation
https://doi.org/10.1108/HFF0820210522
09615539
10.1108/HFF0820210522
P.Gilotte
I.Mortazavi
A.Colon de Carvajal
S.Edwige
C. N.Nayeri
article
Humbert2021
Effect of an azimuthal mean flow on the structure and stability of thermoacoustic modes in an annular combustor model with electroacoustic feedback
2021
6
143
6
10
Thermoacoustic oscillations in axisymmetric annular combustors are generally coupled by degenerate azimuthal modes, which can be of standing or spinning nature. Symmetry breaking due to the presence of a mean azimuthal flow splits the degenerate thermoacoustic eigenvalues, resulting in pairs of counterspinning modes with close but distinct frequencies and growth rates. In this study, experiments have been performed using an annular system where the thermoacoustic feedback due to the flames is mimicked by twelve identical electroacoustic feedback loops. The mean azimuthal flow is generated by fans. We investigate the standing/spinning nature of the oscillations as a function of the azimuthal Mach number for two types of initial states and how the stability of the system is affected by the mean azimuthal flow. It is found that spinning, standing, or mixed modes can be encountered at very low Mach number, but increasing the mean velocity promotes one spinning direction. At sufficiently high Mach number, only spinning modes are observed in the limit cycle oscillations. In some cases, the initial conditions have a significant impact on the final state of the system. It is found that the presence of a mean azimuthal flow increases the acoustic damping. This has a beneficial effect on stability: it often reduces the amplitude of the selfsustained oscillations, and can even suppress them in some cases. However, we observe that the suppression of a mode due to the mean flow may destabilize another one. We discuss our findings in relation to an existing loworder model.
GTP201401
thermoacoustic oscillations, electroacoustic feedback, annular combustor, azimuthal mean flow, acoustic damping
https://doi.org/10.1115/1.4048693
English
doi.org/10.1115/1.4048693
S.Humbert
J.Moeck
A.Orchini
C. O.Paschereit
article
PerezBecker2021
Active flap control with the trailing edge flap hinge moment as a sensor: Using it to estimate local blade inflow conditions and to reduce extreme blade loads and deflections.
Wind Energy Science
2021
6
3
791  814
Active trailing edge flaps are a promising technology that can potentially enable further increases in wind turbine sizes without the disproportionate increase in loads, thus reducing the cost of wind energy even further. Extreme loads and critical deflections of the blade are designdriving issues that can effectively be reduced by flaps. In this paper, we consider the flap hinge moment as a local input sensor for a simple flap controller that reduces extreme loads and critical deflections of the DTU 10 MW Reference Wind Turbine blade. We present a model to calculate the unsteady flap hinge moment that can be used in aeroelastic simulations in the time domain. This model is used to develop an observer that estimates the local angle of attack and relative wind velocity of a blade section based on local sensor information including the flap hinge moment of the blade section. For steady wind conditions that include yawed inflow and wind shear, the observer is able to estimate the local inflow conditions with errors in the mean angle of attack below 0.2∘ and mean relative wind speed errors below 0.4 %. For fully turbulent wind conditions, the observer is able to estimate the lowfrequency content of the local angle of attack and relative velocity even when it is lacking information on the incoming turbulent wind. We include this observer as part of a simple flap controller to reduce extreme loads and critical deflections of the blade. The flap controller's performance is tested in load simulations of the reference turbine with active flaps according to the IEC 614001 power production with extreme turbulence group. We used the lifting line free vortex wake method to calculate the aerodynamic loads. Results show a reduction of the maximum outofplane and resulting blade root bending moments of 8 % and 7.6 %, respectively, when compared to a baseline case without flaps. The critical blade tip deflection is reduced by 7.1 %. Furthermore, a sector load analysis considering extreme loading in all load directions shows a reduction of the extreme resulting bending moment in an angular region covering 30∘ around the positive outofplane blade root bending moment. Further analysis reveals that a fast reaction time of the flap system proves to be critical for its performance. This is achieved with the use of local sensors as input for the flap controller. A larger reduction potential of the system is identified but not reached mainly because of a combination of challenging controller objectives and the simple controller architecture.
https://doi.org/10.5194/wes67912021
doi.org/10.5194/wes67912021
S.PerezBecker
D.Marten
C. O.Paschereit
article
SotoValle2021
Airfoil shaped vortex generators applied on a research wind turbine
AIAA 2021
2021
1413
Vortex generators (VGs) are often used to optimize the flow on wind turbine rotor blades, enhancing the annual energy production between 13% with particular focus on the underperforming aerodynamics in the blades root zone. This has generated great interest among the scientific community, proposing new geometries, besides the common rectangular and triangular layouts. These have been tested on 2D experimental setups and computational approaches, showing lower drag penalties and improved glide ratios. This paper presents an experimental comparison between three VG geometries: rectangular, triangular and ClarkY shaped. The VGs are mounted on a research scale wind turbine model, operated in the wind tunnel of the Technische Universität Berlin. The performance is analyzed at different operational conditions by means of blade surface pressure and root bending moments.
11 – 15 & 19 – 21 January. 2021
https://arc.aiaa.org/doi/10.2514/6.20211413
10.2514/6.20211413
R.SotoValle
S.Bartholomay
M.Manolesos
C. N.Nayeri
C. O.,Paschereit
article
O'Neill2021
Application of SPOD analysis to PIV data obtained in the wake of a circular cylinder undergoing vortex induced vibrations
14th International Symposium on Particle Image Velocimetry – ISPIV 2021
2021
1
1
10
Vortex induced vibrations (VIV) of a circular cylinder have been investigated experimentally using a cyberphysical apparatus with m∗=8, ζ=0.005, and Re=4000. This study considers the application of proper orthogonal decomposition (POD) and spectral POD (SPOD) analysis to the wake dynamics of the lowmassratio VIV of a circular cylinder in the lower branch at U∗=7.5. SPOD has been previously shown to better separate frequencycentered modal dynamics, compared to POD. Coherent POD and SPOD modes were compared and the newly separated third SPOD mode pair was found to have a periodicity characteristic of vortex shedding and a peak in the temporal coefficient spectra at St=f D/U∞=0.2248. The literature has identified that the wake dynamics within the lower branch are synchronized to the cylinder motion; however the present study suggests that some hidden dynamics persist at the Strouhal frequency. Low order models based on the first eight POD and SPOD modes were compared, and it was found that the filtering operationin SPOD removes the uncorrelated stochastic energy component of the POD modes while producing a comparable representation of the coherent deterministic part of the wake dynamics. Using SPOD to separate the distinct frequencycentered dynamics into unique, interpretable mode pairs will simplify future efforts to develop sparse dynamical models of the flow.
https://soremo.library.iit.edu/index.php/ISPIV/article/view/87/95
C. M.O'Neill
Y.Schubert
M.Sieber
R.Martinuzzi
C.Morton
article
PerezBecker2021
Implementation and validation of an advanced wind energy controller in aeroservoelastic simulations using the lifting line free vortex wake model
Energies
2021
14
3
Accurate and reproducible aeroelastic load calculations are indispensable for designing modern multiMW wind turbines. They are also essential for assessing the load reduction capabilities of advanced wind turbine control strategies. In this paper, we contribute to this topic by introducing the TUB Controller, an advanced opensource wind turbine controller capable of performing full load calculations. It is compatible with the aeroelastic software QBlade, which features a lifting line free vortex wake aerodynamic model. The paper describes in detail the controller and includes a validation study against an established opensource controller from the literature. Both controllers show comparable performance with our chosen metrics. Furthermore, we analyze the advanced load reduction capabilities of the individual pitch control strategy included in the TUB Controller. Turbulent wind simulations with the DTU 10 MW Reference Wind Turbine featuring the individual pitch control strategy show a decrease in the outofplane and torsional blade root bending moment fatigue loads of 14% and 9.4% respectively compared to a baseline controller.
wind energy; wind turbine control; load mitigation; individual pitch control; lifting line free vortex wake; vortex methods
https://www.mdpi.com/19961073/14/3/783
S.PerezBecker
D.Marten
C. N.Nayeri
C. O.Paschereit
article
M{\"U}ller2021
Prediction of vortex precession in the draft tube of a model hydro turbine using mean field stability theory and stochastic modelling
IOP Conf. Series: Earth and Environmental Science 774 (2021) 012003, IOP Publishing
2021
774
1
10
In this work we employ mean field stability theory (MFST) to predict the onset of the precessing vortex core (PVC) in the draft tube of Francis turbines. MFST is based on the linear stability analysis of the mean field of turbulent flows. Recent work shows that MFST very accurately predicts the formation of coherent structures in turbulent shear flows, such as the PVC. MFST may further reveal the flow regions that are most susceptible to flow actuation to suppress the PVC, which is of great practical relevance. In this work, MFST is accompanied by a datadriven approach to predict the linear growth rate of the PVC based on pointwise wall pressure measurements. The method is based on statistical evaluation of the probability density function of the PVC amplitude at limit cycle. It makes use of the intense noise induced by the background turbulence, which is expected to be a major driver of hydrodynamic instabilities. The empirical and analytic results are compared to phaselocked LDV measurements conducted inside the draft tube at various operating conditions, to assess the quantitative accuracy of the approach. The methodologies outlined in this work will be of relevance for future design of hydro turbines to run stable over a wide range of operating conditions.
15 Jun 2021 DOI http://dx.doi.org/10.1088/17551315/774/1/012003
17551307
10.1088/17551315/774/1/012003
J.Müller
M.Sieber
I.Litvinov
S.Shtork
S.Alekseenko
K.Oberleithner
article
Barholomay2021
Pressurebased lift estimation and its application to feed forward load control employing trailingedge flaps
eawe, Wind Energy Science
2021
6
221  245
This experimental load control study presents results of an active trailingedge flap feedforward controller for wind turbine applications. The controller input is derived from pressurebased lift estimation methods that rely either on a quasisteady method, based on a threehole probe, or on an unsteady method that is based on three selected surface pressure ports. Furthermore, a standard feedback controller, based on force balance measurements, is compared to the feedforward control. A ClarkY airfoil is employed for the wing that is equipped with a trailingedge flap of x=c D 30% chordwise extension. Inflow disturbances are created by a twodimensional active grid. The Reynolds number is Re D 290000, and reduced frequencies of k D 0:07 up to k D 0:32 are analyzed. Within the first part of the paper, the lift estimation methods are compared. The surfacepressurebased method shows generally more accurate results, whereas the threehole probe estimate overpredicts the lift amplitudes with increasing frequencies. Nonetheless, employing the latter as input to the feedforward controller is more promising as a beneficial phase lead is introduced by this method. A successful load alleviation was achieved up to reduced frequencies of k D 0:192.
ttps://doi.org/10.5194/wes62212021
doi.org/10.5194/wes62212021
S.Bartholomay
T.Wester
S.PerezBecker
S.Konze
C.Menzel
M.Hölling
A.Spickenheuer
J.Peinke
C. N.Nayeri
C. OPaschereit
KilianOberleithner K.
incollection
Schubert2021
Datadriven identification of robust loworder models for dominant dynamics in turbulent flows
2021
267
159  165
iTi 2021: Progress in Turbulence IX
Ramis, Ö. and Talamelli, A. and Peinke, J. and Oberlack, M.
Springer
Cham
Springer eBook Collection
Springer Proceedings in Physics
9783030807153
10.1007/9783030807160
Y.Schubert
M.Sieber
K.Oberleithner
R.Martinuzzi
article
VonSaldern2020a
Analysis of thermoacoustic modes in canannular combustors using effective blochtype boundary conditions
Journal of Engineering for Gas Turbines and Power
2020
11
19
Heavyduty gas turbines are commonly designed with canannular combustors, in which all flames are physically separated. Acoustically, however, the cans communicate via the upstream located compressor plenum, or at the downstream gaps found at the transition to the turbine inlet. In the present study, a coupling condition that is based on a Rayleigh conductivity and acoustic flux conservation is derived. It enables acoustic communication between adjacent cans, in which onedimensional acoustic waves propagate. In addition, because canannular systems commonly feature a discrete rotational symmetry, the acoustic field can be expressed as a Blochperiodic wave in the azimuthal direction. We demonstrate how the coupling conditions resulting in a combustion system with $N$ cans can be expressed as an effective impedance for a single can. By means of this Blochtype boundary condition, the thermoacoustics of a canannular system can be analyzed considering only one can, thus reducing the size of the problem by a factor of N. Using this method, we investigate in frequency domain the effect of the coupling strength of a generic canannular combustor consisting of 12 identical cans, which are connected at the downstream end. We describe generic features of canannular systems and derive results on the frequency response of the cans at various Bloch numbers in the lowfrequency and highfrequency limits. Furthermore, the formation of eigenvalue clusters with eigenvalues of close frequency and growth rate, but very different mode shapes is discussed.
Boundaryvalue problems, combustion chambers, acoustics, eigenvalues, waves, combustion systems, compressors, electrical conductivity, flames, frequency response, gas turbines, ode shapes, hermal conductivity,tThermoacoustics, turbines
https://asmedigitalcollection.asme.org/gasturbinespower/article/doi/10.1115/1.4049162/1091623/AnalysisofThermoacousticModesinCanAnnular
07424795
10.1115/1.4049162
J.von Saldern
A.Orchini
J.Moeck
article
Saverin2020
Advances toward a lightweight, variable fidelity wake simulation tool
Journal of Physics: Conference Series
2020
1618
052070
A method is presented which aims to bridge the gap between overly simplified momentumbased wake models and overly demanding finite volume models of wind turbine wake evolution. The method has been developed to allow an essentially userdefined resolution of the wake. Beyond this, all dominant field quantities are automatically resolved by the solver including convection velocity, shear stress and turbulence intensity. Two distinct methods of solution are presented which both have strengths and weaknesses, the choice of which model being fidelity and application dependent. Both methods make use of multilevel spatial integration to allow greatly improved computational efficiency. The method is here presented for 2D flow in the symmetry plane of a vertical axis wind turbine as an initial demonstration of the potential of the method.
https://doi.org/10.1088/17426596/1618/5/052070
10.1088/17426596/1618/5/052070
J.Saverin
D.Marten
N.Nayeri
C. O.Paschereit
article
Alber2020
Aerodynamic effects of Gurney Flaps on the rotor blades of a research wind turbine
Wind Energy Science
2020
5
4
16451662
https://wes.copernicus.org/articles/5/1645/2020/
10.5194/wes516452020
J.Alber
R.SotoValle
M.Manolesos
S.Bartholomay
C. N.Nayeri
M.Schönlau
C.Menzel
C. O.Paschereit
J.Twele
J.Fortmann
article
PerezBecker2020
Blade element momentum theory overestimating wind turbine loads? – An aeroelastic comparison between OpenFAST’s AeroDyn and QBlade’s LiftingLine Free Vortex Wake method”
Wind Energy Science, vol. 5, pp. 721–743,(2020)
2020
5
5
721743
Load calculations play a key role in determining the design loads of different wind turbine components. To obtain the aerodynamic loads for these calculations, the industry relies heavily on the Blade Element Momentum (BEM) theory. BEM methods use several engineering correction models to capture the aerodynamic phenomena present in Design Load Cases (DLCs) with turbulent wind. Because of this, BEM methods can overestimate aerodynamic loads under challenging conditions when compared to higherorder aerodynamic methods – such as the LiftingLine Free Vortex Wake (LLFVW) method – leading to unnecessarily high design loads and component costs. In this paper, we give a quantitative answer to the question of load overestimation of a particular BEM implementation by comparing the results of aeroelastic load calculations done with the BEMbased OpenFAST code and the QBlade code, which uses a particular implementation of the LLFVW method. We compare extreme and fatigue load predictions from both codes using sixtysix 10 min load simulations of the Danish Technical University (DTU) 10MW Reference Wind Turbine according to the IEC 614001 power production DLC group. Results from both codes show differences in fatigue and extreme load estimations for the considered sensors of the turbine. LLFVW simulations predict 9% lower lifetime damage equivalent loads (DELs) for the outofplane blade root and the tower base fore–aft bending moments compared to BEM simulations. The results also show that lifetime DELs for the yawbearing tilt and yaw moments are 3% and 4% lower when calculated with the LLFVW code. An ultimate state analysis shows that extreme loads of the blade root outofplane bending moment predicted by the LLFVW simulations are 3% lower than the moments predicted by BEM simulations. For the maximum tower base fore–aft bending moment, the LLFVW simulations predict an increase of 2 %. Further analysis reveals that there are two main contributors to these load differences. The first is the different way both codes treat the effect of the nonuniform wind field on the local blade aerodynamics. The second is the higher average aerodynamic torque in the LLFVW simulations. It influences the transition between operating modes of the controller and changes the aeroelastic behavior of the turbine, thus affecting the loads.
https://doi.org/10.5194/wes57212020
10.5194/wes57212020
S.PerezBecker
F.Papi
J.Saverin
D.Marten
A.Biancini
C. O.Paschereit
article
Noack_14092020
Clusterbased network model
Journal of Fluid Mechanics
2020
906
21
141
We propose an automatable datadriven methodology for robust nonlinear reducedordermodelling from timeresolved snapshot data. In the kinematical coarsegraining, thesnapshots are clustered into a few centroids representing the whole ensemble. Thedynamics is conceptualized as a directed network, where the centroids represent nodesand the directed edges denote possible finitetime transitions. The transition probabilitiesand times are inferred from the snapshot data. The resulting clusterbased network modelconstitutes a deterministic–stochastic greybox model resolving the coherentstructureevolution. This model is motivated by limitcycle dynamics, illustrated for the chaoticLorenz attractor and successfully demonstrated for the laminar twodimensional mixinglayer featuring Kelvin–Helmholtz vortices and vortex pairing, and for an actuatedturbulent boundary layer with complex dynamics. Clusterbased network modelling opensa promising new avenue with unique advantages over other modelorder reductions basedon clustering or proper orthogonal decomposition.
lowdimensional models, shear layers, turbulent boundary layers
https://www.cambridge.org/core/journals/journaloffluidmechanics/article/clusterbasednetworkmodel/8252D04A5438ED01E624A7C41CCF81BB
https://doi.org/10.1017/jfm.2020.785
H.Li
D.Fernex
J.Tan
MorzynskiM.
B. R.Noack
article
Balduzzi2020
Combined numerical and experimental study on the use of Gurney Flaps for the performance enhancement of NACA0021 airfoil in static and dynamic conditions
ASME Digital Collection
2020
Power augmentation devices in wind energy applications have been receiving increasing interest from both the scientific and the industrial community. In particular, Gurney Flaps (GFs) showed a great potential thanks to the passive functioning, the simple construction and the possibility to add them as a retrofit to existing rotors. Within this context, the authors have performed an extended investigation on the lift increase capabilities of GFs for the wellknown NACA 0021 airfoil, which has been used in several wind energy applications up to now. The present paper shows the results of a combined experimental and numerical analysis considering different geometrical configurations of the flaps under both static and dynamic conditions. Experimental data were first obtained for the AoA range of 180 degrees at a Reynolds number of 180 k to analyze the impact of three different geometrical configurations of the GF on the aerodynamic behavior. The geometrical configurations were defined by varying the length of the flap (1.4 % and 2.5 % of the chord) and its inclination angle with respect to the blade chord (90 degrees and 45 degrees). The experimental investigation involved also dynamic sinusoidal pitching movements at multiple reduced frequencies to evaluate the stall hysteresis cycle. An unsteady CFD numerical model was calibrated against wind tunnel data and then exploited to extend the investigation to a wider range of Reynolds numbers for dynamic AoA rates of change typical of verticalaxis wind turbines, i.e. characterized by higher reduced frequencies with a nonsinusoidal motion law.
https://doi.org/10.1115/1.4048908
F.Balduzzi
D.Holst
P. F.Melani
F.Wegner
C. N.Nayeri
G.Ferrara
C. O.Paschereit
A.Bianchini
article
SotoValle_2020
Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements
Wind Energy Science Discussions
2020
128
In this paper, a method to determine the angle of attack on a wind turbine rotor blade using a chordwise pressure distribution measurement was applied. The approach uses a reduced number of pressure taps data located close to the blade leading edge. The results were compared with three 3hole probes located at different radial positions and analytical calculations. The experimental approaches are based on the 2D flow assumption; the pressure tap method is an application of the thin airfoil theory and the 3hole probe method uses external probe measurements and applies geometrical and induction corrections.The experiments were conducted in the wind tunnel at the Hermann Föttinger Institut of the Technische Unversität Berlin. The research turbine is a threebladed upwind horizontal axis wind turbine model with a rotor diameter of 3 m. The measurements were carried out at rated condition with a tip speed ratio of 4.35 and different yaw and pitch angles were tested in order to compare both methods over a wide range of conditions.Results show that the pressure taps method is suitable with a similar angle of attack results as the 3hole probes for the aligned case. When a yaw misalignment was introduced the method captures the same trend and feature of the analytical estimations. Nevertheless, it is not able to capture the tower influence. Regarding the influence of pitching the blades, a linear relationship between the angle of attack and pitch angle was found.
https://wes.copernicus.org/preprints/wes202035/
10.5194/wes202035
R.SotoValle
S.Bartholomay
J.Alber
M.Manolesos
C. N.Nayeri
C. O.Paschereit
article
Noack07022020
Drag reduction and energy savings by spanwise travelling surface waves for flat plate flow
Flow Turbulence Combustion
2020
105
125  157
Wallresolved largeeddy simulations are performed to study the impact of spanwisetraveling transversal surface waves in zeropressure gradient turbulent boundary layer flow.Eighty variations of wavelength, period, and amplitude of the space and timedependentsinusoidal wall motion are considered for a boundary layer at a momentum thickness basedReynolds number of Re= 1000 . The results show a strong decrease of friction drag of upto 26% and considerable net power saving of up to 10% . However, the highest net powersaving does not occur at the maximum drag reduction. The drag reduction is modeled asa function of the actuation parameters by support vector regression using the LES data.A dependence of the spanwise pressure drag on the wavelength is found. A substantialattenuation of the nearwall turbulence intensity and especially a weakening of the nearwallvelocity streaks are observed. Similarities between the current actuation techniqueand the method of a spanwise oscillating wall without any normal surface deflection arereported. In particular, the generation of a directional spanwise oscillating Stokes layer isfound to be related to skinfriction reduction.
Turbulent boundary layer Drag reduction Transversal traveling surface wave Largeeddy simulation ·Active flow control
https://link.springer.com/article/10.1007/s10494020001108
15731987,13866184
https://doi.org/10.1007/s10494020001108
M.Albers
P. S.Meysonnat
D.Fernex
R.Semaan
B. R.Noack
W.Schröder
article
MüllerVahl2020
Dynamic stall under combined pitching and surging
AIAA Journal
2020
58
12
51345145
https://arc.aiaa.org/doi/pdf/10.2514/1.J059153
10.2514/1.j059153
H. F.MüllerVahl
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
article
Noack02102020
Loworder model for successive bifurcations of the fluidic pinball
Journal of Fluid Mechanics
2020
884
A37
139
We propose the first leastorder Galerkin model of an incompressible flow undergoingtwo successive supercritical bifurcations of Hopf and pitchfork type. A key enableris a meanfield consideration exploiting the symmetry of the mean flow and theasymmetry of the fluctuation. These symmetries generalize meanfield theory,e.g. no assumption of slow growth rate is needed. The resulting fivedimensionalGalerkin model successfully describes the phenomenogram of the fluidic pinball, atwodimensional wake flow around a cluster of three equidistantly spaced cylinders.The corresponding transition scenario is shown to undergo two successive supercriticalbifurcations, namely a Hopf and a pitchfork bifurcation on the way to chaos. Thegeneralized meanfield Galerkin methodology may be employed to describe othertransition scenarios.
bifurcation, lowdimensional models, wakes
https://www.cambridge.org/core/journals/journaloffluidmechanics/article/lowordermodelforsuccessivebifurcationsofthefluidicpinball/31E74B80FB2571D10D5166039B991BB3#
00221120
https://dx.doi.org/10.1017/jfm.2019.959
N.Deng
B. R.Noack
M.Morzyński
L. R.Pastur
article
Noack_10012020
Machine learning strategies applied to the control of a fluidic pinball
Physics of Fluids
2020
32
1
113
The wake stabilization of a triangular cluster of three rotating cylinders is investigated. Experiments are performed at Reynolds number Re ∼ 2200. Flow control is realized using rotating cylinders spanning the windtunnel height. The cylinders are individually connected to identical brushless DC motors. Twocomponent planar particle image velocimetry measurements and constant temperature hotwire anemometry were used to characterize the flow without and with actuation. Main openloop configurations are studied and different controlled flow topologies are identified. Machine learning control is then implemented for the optimization of the flow control performance. Linear genetic algorithms are used here as the optimization technique for the openloop constant speedactuators. Two different cost functions
015108
https://aip.scitation.org/doi/10.1063/1.5127202
10706631
https://doi.org/10.1063/1.5127202
C.Raibaudo
P.hong
B. R.Noack
R. J.Martinuzzi
article
vonSaldern2020
Nonlinear interaction between clustered unstable thermoacoustic modes in canannular combustors
Proceedings of the Combustion Institute
2020
A canannular combustor consists of a set of nominally identical cans, in which the flames burn in an essentially isolated manner. However, adjacent cans are able to communicate acoustically, which provides dynamic coupling of the entire canannular arrangement. Recently, it was shown that the acoustic coupling is not negligible and can cause clustering of eigenfrequencies. In this study, we present a loworder modeling framework for selfexcited thermoacoustic oscillations in generic canannular combustors consisting of N identical cans. The dynamics of the flames are modeled with the nonlinear Gequation; the acoustic model accounts for plane acoustic waves inside the cans and cantocan communication. The latter is enabled through a coupling boundary condition that is based on conservation of mass and a Rayleigh conductivity. For weak coupling between adjacent cans, the thermoacoustic feedback cycle shows clusters of linearly unstable modes of different azimuthal order, which are close in frequency and growth rate. Their interaction in the nonlinear regime is investigated using timedomain simulations. Two simulations for generic canannular combustors consisting of 4 and 6 cans with weak acoustic coupling are discussed in this study. We observe a strong interaction between the modes, which can cause long transition times and allows modes that do not dominate the system dynamics in the linear regime to be dominant in the nonlinear regime. While the N=6 case converges to a periodic oscillation pattern with one dominant frequency, the N=4 case converges to a quasiperiodic oscillation involving modes of different azimuthal order. Moreover, we observe a synchronization of these modes. These results raise the questions whether it is possible to predict which mode(s) will dominate the system in the saturated state and under which conditions synchronization of clustered modes can occur.
Canannular combustor, thermoacoustics, nonlinear interaction, weak coupling, kinematic flame model
https://www.sciencedirect.com/science/article/pii/S154074892030328X
15407489
https://doi.org/10.1016/j.proci.2020.06.236
J.von Saldern
J.Moeck
A.Bianchini
article
marten2020predicting
Predicting wind turbine wake breakdown using a free vortex wake code
AIAA Journal
2020
58
11
46724685
https://arc.aiaa.org/doi/10.2514/1.J058308
American Institute of Aeronautics and Astronautics
00011452
10.2514/1.J058308
D.Marten
C. O.Paschereit
X.Huang
M.Meinke
W.Schröder
J.Müller
K.Oberleithner
article
Müller2020
Receptivity of the turbulent precessing vortex core: Synchronization experiments and global adjoint linear stability analysis
Journal of Fluid Mechanics
2020
888
A3
https://www.cambridge.org/core/product/identifier/S0022112019010632/type/journal{\_}article
Cambridge University Press
00221120
10.1017/jfm.2019.1063
J.Müller
F.Lückoff
P.Paredes
V.Theofilis
K.Oberleithner
article
Vanierschot2020
Single and doublehelix vortex breakdown as two dominant global modes in turbulent swirling jet flow
Journal of Fluid Mechanics
2020
883
A31
https://www.cambridge.org/core/product/identifier/S0022112019008723/type/journal{\_}article
Cambridge University Press (CUP)
00221120
10.1017/jfm.2019.872
M.Vanierschot
J.Müller
M.Sieber
M.Percin
B.van Oudheusden
K.Oberleithner
article
Noack_20042020
Upstream actuation for bluffbody wake control driven by a genetically inspired optimization
Journal of Fluid Mechanics
2020
893
1
129
The control of bluffbody wakes for reduced drag and enhanced stability hastraditionally relied on the socalled directwake control approach. By the use ofactuators or passive devices, one can manipulate the aerodynamic loads that act on therear of the model. An alternative approach for the manipulation of the flow is to movethe position of the actuator upstream, hence interacting with an easiertomanipulateboundary layer. The present paper comprises a bluffbody flow study via largeeddysimulations to investigate the effectiveness of an upstream actuator (positioned atthe leading edge) with regard to the manipulation of the wake dynamics and itsaerodynamic loads. A rectangular cylinder with rounded leading edges, equippedwith actuators positioned at the front curvatures, is simulated at Re = 40 000. Agenetic algorithm (GA) optimization is performed to find an effective actuation thatminimizes drag. It is shown that the GA selects superharmonic frequencies of thenatural vortex shedding. Hence, the induced disturbances, penetrating downstreamin the wake, significantly reduce drag and lateral instability. A comparison witha siderecirculationsuppression approach is also presented, the latter case beingworse in terms of reduced drag (only 8 % drag reduction achieved), despite thetotal suppression of the side recirculation bubble. In contrast, the GA optimizedcase contributes to a 20 % drag reduction with respect to the unactuated case. Inaddition, the large drag reduction is associated with a reduced shedding motion andan improved lateral stability.
https://www.cambridge.org/core/journals/journaloffluidmechanics/article/upstreamactuationforbluffbodywakecontroldrivenbyageneticallyinspiredoptimization/19BE0FE035B7FAB78E947B2E693B21C5
https://doi.org/10.1017/jfm.2020.220
G.Minelli
T.Dong
B. R.Noack
S.Krajnovic
article
SotoValle2020
Wind turbine tip vortices under the influence of wind tunnel blockage effects
Journal of Physics: Conference Series
2020
1618
032045
The current paper describes the characteristics of the tip vortex in the near wake of a threebladed upwind horizontal axis wind turbine with arotor diameter of 3 m. Phaselocked stereo particle image velocimetry measurements were carried out under the inuence of the windtunnel walls that create a high blockage ratio. The location of the vortex, convection velocity, core radius, and strength were investigated and compared with similar investigations, including dierent blockages cases. Additionally, the same performance of the wind turbine model wassimulated in the open source wind turbine tool QBlade, using the lifting line free vortex wake module in the absence of the walls.The results showed that the location of the tip vortices was more inboard the tip and more downstream the tunnel compared to the simulations and similar experiments. The convection velocity remained similar in the axial direction and changed in the lateral direction, contributingto the delay of the movement of the tip vortex outboard the tip. The strength, based on the circulation, was found with a dierence of 4% between simulation and experiment.�
https://doi.org/10.1088/17426596/1618/3/032045
10.1088/17426596/1618/3/032045
R.SotoValle
J.Alber
M.Manolesos
C. N.Nayeri
C. O.Paschereit
inproceedings
Müller2020b
Prediction of vortex precession in the draft tube of a model hydro turbine using mean field stability theory and stochastic modelling
2020
Lausanne, Switzerland
30th Symposium on Hydraulic Machinery and Systems 2020
IAHR
J.Müller
M.Sieber
I.Litvinov
S.Shtork
S.Alekseenko
K.Oberleithner
article
Tschepe2019
Die Rolle der Aerodynamik bei der Energieeinsparung von modernen Schienenfahrzeugen und Hyperloop
ETR
2019
7
5
Aerodynamics referring to energy saving of modern rail vehicles and hyperloops The present article shows that aerodynamics plays an important role and has a large proportion in the rail vehicles’ energy consumption. It is about 40 – 50 % in highspeed rails or freight transports. While in the passenger transport energy savings of approximately 6 – 8 % is possible by aerodynamics measures, the potential in freight transport shall be even 8 – 10 %. In order to use this possibility sensibly, a greater consideration of the lifecyclecosts for freight and regional rails in the tendering process is necessary.
TschepeJ.
NayeriC. N.
HechtM.
article
Marten2019
Benchmark of a novel aeroelastic simulation code for small scale VAWT analysis
ASME
2019
141
4
13
After almost 20 years of absence from research agendas, interest in the vertical axis wind turbine (VAWT) technology is presently increasing again, after the research stalled in the mid 90's in favor of horizontal axis wind turbines (HAWTs). However, due to the lack of research in past years, there are a significantly lower number of design and certification tools available, many of which are underdeveloped if compared to the corresponding tools for HAWTs. To partially fulfill this gap, a structural finite element analysis (FEA) model, based on the Open Source multiphysics library PROJECT::CHRONO, was recently integrated with the lifting line free vortex wake (LLFVW) method inside the Open Source wind turbine simulation code QBlade and validated against numerical and experimental data of the SANDIA 34 m rotor. In this work, some details about the newly implemented nonlinear structural model and its coupling to the aerodynamic solver are first given. Then, in a continuous effort to assess its accuracy, the code capabilities were here tested on a smallscale, fastspinning (up to 450 rpm) VAWT. The study turbine is a helix shaped, 1 kW Darrieus turbine, for which other numerical analyses were available from a previous study, including the results coming from both a onedimensional beam element model and a more sophisticated shell element model. The resulting data represented an excellent basis for comparison and validation of the new aeroelastic coupling in QBlade. Based on the structural and aerodynamic data of the study turbine, an aeroelastic model was then constructed. A purely aerodynamic comparison to experimental data and a blade element momentum (BEM) simulation represented the benchmark for QBlade aerodynamic performance. Then, a purely structural analysis was carried out and compared to the numerical results from the former. After the code validation, an aeroelastically coupled simulation of a rotor selfstart has been performed to demonstrate the capabilities of the newly developed model to predict the highly nonlinear transient aerodynamic and structural rotor response.
GTP181489
Blades, Rotors, Simulation, Turbines, Vertical axis wind turbines, Modal analysis, Flow (Dynamics), Vortices
https://asmedigitalcollection.asme.org/gasturbinespower/article/141/4/041014/367187/BenchmarkofaNovelAeroElasticSimulationCode
English
doi.org/10.1115/1.4041519
D.Marten
M.Lenni
G.Pechlivanoglu
C. O.Paschereit
A.Bianchini
A.Ferrara
L.Ferrari
article
Saverin2018
Comparison of experimental and numerically predicted threedimensional wake behaviour of a vertical axis wind turbine
Journal of Engineering Gas Turbine Power
2018
4
12
The evolution of the wake of a wind turbine contributes significantly to its operation and performance, as well as to those of machines installed in the vicinity. The inherent unsteady and threedimensional aerodynamics of Vertical Axis Wind Turbines (VAWT) have hitherto limited the research on wake evolution. In this paper the wakes of both a troposkien and a Htype VAWT rotor are investigated by comparing experiments and calculations. Experiments were carried out in the largescale wind tunnel of the Politecnico di Milano, where unsteady velocity measurements in the wake were performed by means of hot wire anemometry. The geometry of the rotors was reconstructed in the opensource windturbine software QBlade, developed at the TU Berlin. The aerodynamic model makes use of a lifting line freevortex wake (LLFVW) formulation, including an adapted BeddoesLeishman unsteady aerodynamic model; airfoil polars are introduced to assign sectional lift and drag coefficients. A wake sensitivity analysis was carried out to maximize the reliability of wake predictions. The calculations are shown to reproduce several wake features observed in the experiments, including bladetip vortex, dominant and submissive vortical structures, and periodic unsteadiness caused by sectional dynamic stall. The experimental assessment of the simulations illustrates that the LLFVW model is capable of predicting the unsteady wake development with very limited computational cost, thus making the model ideal for the design and optimization of VAWTs.
GTP171608
http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=2678430
10.1115/1.4039935
J.Saverin
D.Marten
D.Holst
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
G.Persico
article
Klein2018
About the suitability of different numerical methods to reproduce model wind turbine measurements in a wind tunnel with a high blockage ratio
Wind Energy Science
2018
3
349  460
In the present paper, numerical and experimental investigations of a model wind turbine with a diameter of 3.0 m are described. The study has three objectives. The first one is the provision of validation data. The second one is to estimate the influence of the wind tunnel walls by comparing measurements to simulated results with and without wind tunnel walls. The last objective is the comparison and evaluation of methods of high fidelity, namely computational fluid dynamics, and medium fidelity, namely liftingline free vortex wake. The experiments were carried out in the large wind tunnel of the TU Berlin where a blockage ratio of 40 % occurs. With the liftingline free vortex wake code QBlade, the turbine was simulated under far field conditions at the TU Berlin. Unsteady Reynoldsaveraged Navier–Stokes simulations of the wind turbine, including wind tunnel walls and under far field conditions, were performed at the University of Stuttgart with the computational fluid dynamics code FLOWer. Comparisons among the experiment, the liftingline free vortex wake code and the computational fluid dynamics code include onblade velocity and angle of attack. Comparisons of flow fields are drawn between the experiment and the computational fluid dynamics code. Bending moments are compared among the simulations. A good accordance was achieved for the onblade velocity and the angle of attack, whereas deviations occur for the flow fields and the bending moments.
https://doi.org/10.5194/wes34392018
10.5194/wes34392018
A. C.Klein
S.Bartholomay
D.Marten
T.Lutz
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
E.Krämer
article
Bartholomay_2018
CrossTalk compensation for blade root flap and edgewise moments on an experimental research wind turbine and comparison to numerical results
Proceedings of he ASME Turbo Expo 2018
2018
9 Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy
GT201876977, pp. V009T48A016
11
In the current paper a method to correct crosstalk effects for straingauge measurements is presented. The method is demonstrated on an experimental horizontal axis wind turbine. The procedure takes crossmoments (flapwise on edgewise moments and vice versa) as well as axial acceleration into account. The results from the experimental setup are compared to numerical URANS calculations and the mediumfidelity code Qblade for a baseline case and two yawed inflow situations.
Oslo, Norway, June 11  15, 2018
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleID=2701583
Bartholomay S., Marten D., Sánchez Martinez M., Alber J., Pechlivanoglou G., Nayeri C. N., Paschereit C. O., Klein A, Lutz Th. and Krämer E.
ASME Turbo Expo 2018
ASME
9780791851180
10.1115/GT201876977
S.Bartholomay
D.Marten
M.Sánchez Martinez
J.Alber
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
A. C.Klein
L.Thorsten
E.Krämer
article
Saverin_2018
Multilevel Simulation of Aerodynamic Singularity Elements
Aerospace Research Central
2018
AIAA 20180254
The development of a multilevel integration scheme is described. The motivating application is the fast analysis of selfinﬂuence of both near and farwake of a wind turbine. By treating the interaction of the wake with the method of singularity elements, the inﬂuence at any point can be expressed as an integral over the domain of the product of a kernel __function and element strength __. In a similar fashion to the wellknown fast multipole method, the region of interest is separated into near and farﬁeld domains with a series of progressive geometric coursening. Element strengths are mapped onto a structured grid of nodes within each domain, or containing box, by using polynomial interpolation. Here barycentric Lagrangian interpolation has been applied with the use of Chebyshevtype node distributions. This method has previously been shown to theoretically reduce the computational expense of the problem from __. The model has been developed to be as general as possible, in order to allow the treatment of a number of different kernel types simultaneously. This expands the applicability to include treatment of singularity elements, wakeboundary interaction and aeroaooustic pressure propagation. Also possible is the extension to surface or volume distributions, making the method applicable to the boundary element method. By comparing the results of the model evaluation achieved with direct evaluation, it is demonstrated that the method works accurately for a number of kernel types including source, dipole and vortex articles methods. The accuracy of the method is shown to be completely controlled by polynomial order P, and an appropriate choice of minimum box sidelength __. The ability of the method to treat vortex particles is demonstrated.
2018 Wind Energy Symposium Kissimmee, Florida
https://arc.aiaa.org/doi/10.2514/6.20180254
10.2514/6.20180254
J.Saverin
D.Marten
C. N.Nayeri
G.Pechlivanoglou
C. O.Paschereit
article
Marten2018
Numerical and Experimental Investigation of Trailing Edge Flap Performance on a Model Wind Turbine Read More: https://arc.aiaa.org/doi/10.2514/6.20181246
Aerospace Research Central
2018
A model to assess the performance of active trailing edge flaps on wind turbine blades has recently been integrated with a Liftigng Line Free Vortex Wake code. Successively the codes ability, to accurately predict the effect of trailing edge flaps on the rotor performance and loads in a steady inflow setting was validated with results from tools of ranging fidelity performance in a more complicated setting including yawed inflow was then carried out. For the second benchmark, results between the vortex code, a CFD code and experimental measurements obtained from a model wind turbine were compared. This comparison also highlights the influence of the wind tunnel walls on the experimental results and shows how the free vortex code can predict the experimental results without explicitly including a model o the wind tunnel.
AIAA SciTech Forum 2018 Wind Energy Symposium, Kissimmee, Florida
https://arc.aiaa.org/doi/10.2514/6.20181246
10.2514/6.20181246
D.Marten
S.Bartholomay
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
A.Fischer
Th.Lutz
conference
PerezBecker_2020
Investigations on the fatigue load reduction potential of advanced control strategies for multiMW wind turbines using a free vortex wake Model
2018
9
This paper presents the results of a fatigue load evaluation from aeroelastic simulations of a multimegawatt wind turbine. Both the Blade Element Momentum (BEM) and the Lifting Line Free Vortex Wake (LLFVW) methods were used to compute the aerodynamic forces. The loads in selected turbine components, calculated from NREL’s FAST v8 using the aerodynamic solver AeroDyn, are compared to the loads obtained using the LLFVW aerodynamics formulation in QBlade. The DTU 10 MW Reference Wind Turbine is simulated in power production load cases at several wind speeds under idealized conditions. The aerodynamic forces and turbine loads are evaluated in detail, showing very good agreement between both codes. Additionally, the turbine is simulated under realistic conditions according to the current design standards. Fatigue loads derived from load calculations using both codes are compared when the turbine is controlled with a basic pitch and torque controller. It is found that the simulations performed with the BEM method generally predict higher fatigue loading in the turbine components. A higher pitch activity is also predicted with the BEM simulations. The differences are larger for wind speeds around rated wind speed. Furthermore, the fatigue reduction potential of the individual pitch control (IPC) strategy is examined and compared when using the two different codes. The IPC strategy shows a higher load reduction of the outofplane blade root bending moments when simulated with the LLFVW method. This is accompanied with higher pitch activity at the actuation frequency of the IPC strategy.
GT201876078, V009T48A008; 11 pages
https://asmedigitalcollection.asme.org/GT/proceedingsabstract/GT2018/51180/V009T48A008/273154
ASME
9780791851180
10.1115/GT201876078
S.PerezBecker
J.Saverin
D.Marten
J.Alber
G.Pechlivanoglou
C. O.Paschereit
proceedings
Edwige2018
Flow Control Around a SUV Simplified Vehicle
ASME 2018 5th Joint USEuropean Fluids Engineering Division Summer Meeting
2018
2 Development and Applications in Computational Fluid Dynamics; Industrial and Environmental Applications of Fluid Mechanics; Fluid Measurement and Instrumentation
The research on the external aerodynamics of ground vehicles can nowadays be related to sustainable development strategies, confirmed by the worldwide CO2 regulation target. Automotive manufacturers estimate that a drag reduction of 30% contributes to 10g/km of CO2 reduction. However, this drag reduction should be obtained without constraints on the design, the safety, comfort and habitability of the passengers. Thus, it is interesting to find flow control solutions, which will remove or remote recirculation zones due to separation edges with appropriate control techniques. In automotive sales, the SUV, 4x4 and compact cars represent a large part of the market share and the study of control approaches for this geometry is practically useful. In this work, appropriate control techniques are designed to decrease the drag forces around a reduced scale SUV car benchmark called POSUV. The control techniques are based on the DMD (Dynamic Mode Decomposition) algorithms generating an optimized drag reduction procedure. It involves independent transient inflow boundary conditions for flow control actuation in the vicinity of the separation zones and time resolved pressure sensor output signals on the rear end surface of the mockup. This study, that exploits dominant flow features behind the tailgate and the rear bumper, is performed using Large Eddy Simulations on a sufficient run time scale, in order to minimize a cost function dealing with the time and space average pressure coefficient. The resulting dynamic modal decomposition obtained by these LES simulations and by wind tunnel measurements has been compared for the reference case, in order to select the most appropriate run time scale. Analysis of the numerical results shows a significant pressure increase on the tailgate, for independent flow control frequencies. Similar decomposition performed in the wake with and without numerical flow control help understanding the flow modifications in the detachment zones.
Montreal, Quebec, Canada, July 15–20, 2018
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2710650
ASME Proceedings  25th Symposium on Industrial and Environmental Applications of Fluid Mechanics
ASME
9780791851562
10.1115/FEDSM201883444
S.Edwige
Ph.Gilotte
I.Mortazavi
Y.Eulalie
D.Holst
C. N.Nayeri
J.L.Aider
E.Varon
article
Lennie2017
Development of a partially stochastic unsteady aerodynamics model
AIAA SciTech Forum
2017
1
https://arc.aiaa.org/doi/abs/10.2514/6.20172002
Aerospace Research Central
10.2514/6.20172002
M.Lennie
J.Wendler
D.Marten
G.Pechlivanoglou
C. O.Paschereit
article
Marten2017
Validation and comparison of a newly developed aeroelastic design code for VAWT
Aerospace Research Central, AIAA SciTech Forum
2017
The open source wind turbine simulation code QBlade, based on a Lifting Line Free Vortex Wake formulation to evaluate the unsteady aerodynamics, recently integrated the PROJECTCHRONO FEA library that, by using EulerBernoulli beams in a corotational formulation, solves for the structural dynamics to achieve an aeroelastic coupling. To validate the newly implemented structural model its performance is compared to literature data and two other finite element computer codes. The comparison is based on a modal analysis and aeroelastic simulations of the SNL 34m VAWT testbed, for which the aerodynamic and structural properties are well known. The structural loads are obtained from IE C 614001 design load cases. In one of the calculated load cases an aeroelastic instability could be observed which confirms similar observations that have previously been reported in the literature.
35th Wind Energy Symposium 9  13 January 2017 Grapevine, Texas
http://dx.doi.org/10.2514/MWES17
10.2514/6.20170452
D.Marten
M.Lennie
G.Pechlivanoglou
C. O.Paschereit
N. V.Dy
I.Paraschivoiu
F.Saeed
inbook
Menzel2017
Visualisierungswindkanal (ViWiKa) für Messe, Forschung und Lehre auf Basis von myRIO1900
2017
430  434
http://www.etz.de/files/10_02_menzelholstfischer.pdf
Rahman J., Heinze R.
VDE Verlag
Forschung und Lehre in Virtuelle Instrumente in der Praxis 2017
978380044411
C.Menzel
D.Holst
J.Fischer
C. N.Nayeri
C. O.Paschereit
inproceedings
Holst2017a
Comparison of Experimental and Numerically Predicted ThreeDimensional Wake Behaviour of a Vertical Axis Wind Turbine
2017
6
9
The evolution of the wake of a wind turbine contributes significantly to its operation and performance, as well as to those of machines installed in the vicinity. The inherent unsteady and threedimensional aerodynamics of Vertical Axis Wind Turbines (VAWT) have hitherto limited the research on wake evolution. In this paper the wakes of both a troposkien and a Htype VAWT rotor are investigated by comparing experiments and calculations. Experiments were carried out in the largescale wind tunnel of the Politecnico di Milano, where unsteady velocity measurements in the wake were performed by means of hot wire anemometry. The geometry of the rotors was reconstructed in the opensource windturbine software QBlade, developed at the TU Berlin. The aerodynamic model makes use of a lifting line freevortex wake (LLFVW) formulation, including an adapted BeddoesLeishman unsteady aerodynamic model; airfoil polars are introduced to assign sectional lift and drag coefficients. A wake sensitivity analysis was carried out to maximize the reliability of wake predictions. The calculations are shown to reproduce several wake features observed in the experiments, including bladetip vortex, dominant and submissive vortical structures, and periodic unsteadiness caused by sectional dynamic stall. The experimental assessment of the simulations illustrates that the LLFVW model is capable of predicting the unsteady wake development with very limited computational cost, thus making the model ideal for the design and optimization of VAWTs.
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2650574
ASME
Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy
ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition
ASME
Charlotte, North Carolina, USA
ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition
26  30 Juni 2017
English
ISBN: 9780791850961
10.1115/GT201764004
J.Saverin
D.Marten
D.Holst
G.Pechlivanloglou
C. N.Nayeri
C. O.Paschereit
article
Lennie2016
Modern methods for investigating the stability of a pitching floating platform wind turbine
Journal of Physics
2016
10
Conference Series, 753
http://iopscience.iop.org/article/10.1088/17426596/753/8/082012/meta
IOPscience
10.1088/17426596/753/8/082012
M.Lennie
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
article
Wassmer2016
Measurement and Modeling of the Generation and the Transport of Entropy Waves in a Model Gas Turbine Combustor
2016
5
30
GTRE044
http://www.tumias.de/thermoacoustics2016/focusimpact.html
D.Wassmer
B.Schuermans
C. O.Paschereit
J. P.Moeck
article
Strangfeld2016
Airfoil in a high amplitude oscillating stream
Journal of Fluid Mechanics
2016
4
793
79108
http://journals.cambridge.org/article_S0022112016001269
14697645
10.1017/jfm.2016.126
C.Strangfeld
H.MüllerVahl
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
article
Wendler_2016
An Unsteady Aerodynamics Model for Lifting Line Free Vortex Wake Simulations of HAWT and VAWT in QBlade
Proceedings of ASME Turbo Expo 2016, June 1317, 2016, Seoul, South Korea
2016
9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy
11 Pages
This paper describes the introduction of an unsteady aerodynamics model applicable for horizontal and vertical axis wind turbines (HAWT/VAWT) into the advanced blade design and simulation code QBlade, developed at the HFI of the TU Berlin. The software contains a module based on lifting line theory including a free vortex wake algorithm (LLFVW) which has recently been coupled to the structural solver of FAST to allow for timeresolved aeroelastic simulations of large, flexible wind turbine blades. The aerodynamic model yields an accuracy improvement with respect to Blade Element Momentum (BEM) theory and a more practical approach compared to higher fidelity methods such as Computational Fluid Dynamics (CFD) which are too computationally demanding for load case calculations. To capture the dynamics of flow separation, a semiempirical method based on the BeddoesLeishman model now extends the simple table lookups of static polar data by predicting the unsteady lift and drag coefficients from steady data and the current state of motion. The model modifications for wind turbines and the coupling to QBlade’s vortex method are described. A 2D validation of the implementation is presented in this paper to demonstrate the capability and reliability of the resulting simulation scheme. The applicability of the model is shown for exemplary HAWT and VAWT test cases. The modelling of the dynamic stall vortex, the empiric model constants as well as the influence of the dynamic coefficients on performance predictions are investigated.
Proceedings of ASME Turbo Expo 2016, June 1317, 2016, Seoul, South Korea
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2555667
10.1115/GT201657184
J.Wendler
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
article
Marten2016
Effects of Airfoil's Polar Data in the Stall Region on the Estimation of Darrieus Wind Turbine Performance
ASME
2016
139
2
9
Interest in verticalaxis wind turbines (VAWTs) is experiencing a renaissance after most major research projects came to a standstill in the mid 1990s, in favor of conventional horizontalaxis turbines (HAWTs). Nowadays, the inherent advantages of the VAWT concept, especially in the Darrieus configuration, may outweigh their disadvantages in specific applications, like the urban context or floating platforms. To enable these concepts further, efficient, accurate, and robust aerodynamic prediction tools and design guidelines are needed for VAWTs, for which loworder simulation methods have not reached yet a maturity comparable to that of the blade element momentum theory for HAWTs' applications. The two computationally efficient methods that are presently capable of capturing the unsteady aerodynamics of Darrieus turbines are the double multiple streamtubes (DMS) theory, based on momentum balances, and the lifting line theory (LLT) coupled to a free vortex wake model. Both methods make use of tabulated lift and drag coefficients to compute the blade forces. Since the incidence angles range experienced by a VAWT blade is much wider than that of a HAWT blade, the accuracy of polars in describing the stall region and the transition toward the “thin plate like” behavior has a large effect on simulation results. This paper will demonstrate the importance of stall and poststall data handling in the performance estimation of Darrieus VAWTs. Using validated CFD simulations as a baseline, comparisons are provided for a blade in VAWTlike motion based on a DMS and a LLT code employing three sets of poststall data obtained from a wind tunnel campaign, XFoil predictions extrapolated with the Viterna–Corrigan model and a combination of them. The polar extrapolation influence on quasisteady operating conditions is shown and azimuthal variations of thrust and torque are compared for exemplary tipspeed ratios (TSRs). In addition, the major relevance of a proper dynamic stall model into both the simulation methods is highlighted and discussed.
Paper No: GTP161286
http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=2541658&resultClick=3
10.1115/1.4034326
D.Marten
S.Bianchini
G.Pechlivanoglou
F.Balduzzi
C. N.Nayeri
G.Ferrara
C. O.Paschereit
L.Ferrari
article
Gray_2016
Thermodynamic Evaluation of Pulse Detonation Combustion for Gas Turbine Power Cycles
Proceedings of ASME Turbomachinery Technical Conference & Exposition. Seoul, South Korea, June 13–17, 2016
2016
Volume 4B: Combustion, Fuels and Emissions
Paper No. GT201657813, pp. V04BT04A044
9
Constantvolume (pressuregain) combustion cycles show much promise for further increasing the efficiency of modern gas turbines, which in the last decades have begun to reach the boundaries of modern technology in terms of pressure and temperature, as well as the ever more stringent demands on reducing exhaust gas emissions. The thermodynamic model of the gas turbine consists of a compressor with a polytropic efficiency of 90%, a combustor modeled as either a pulse detonation combustor (PDC) or as an isobaric homogeneous reactor, and a turbine, the efficiency of which is calculated using suitable turbine operational maps. A simulation is conducted using the onedimensional reacting Euler equations to obtain the unsteady PDC outlet parameters for use as turbine inlet conditions. The efficiencies for the Fickett–Jacobs and Joule cycles are then compared. The Fickett–Jacobs cycle shows promise at relatively low compressor pressure ratios, whereas the importance of the harvesting of exhaust gas kinetic energy for the cycle performance is highlighted.
Proceedings of ASME Turbomachinery Technical Conference & Exposition. Seoul, South Korea, June 13 – 17, 2016
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2555111
9780791849767
10.1115/gt201657813
J.Gray
J.Vinkeloe
J. P.Moeck
C. O.Paschereit
P.Stathopoulos
P.Berndt
R.Klein
conference
Marten2016a
Nonlinear Lifting Line Theory Applied To Vertical Axis Wind Turbines: Development of a Practical Design Tool
2016
8
Recently a new interest in vertical axis wind turbine (VAWT) technology is fueled by research on floating support structures for large scale offshore wind energy application. For the application on floating structures at multi megawatt size, the VAWT concept may offer distinct advantages over the conventional horizontal axis wind turbine (HAWT) design. As an example VAWT turbines are better suited for upscaling and, at multi megawatt size, the problem of periodic fatigue cycles reduces significantly due to a very low rotational speed. Additionally, the possibility to store the transmission and electricity generation system at the bottom, compared to the tower top as in a HAWT, can lead to a considerable reduction of material logistics costs. However, as most VAWT research stalled in the mid 90’s, no established and sophisticated tools to investigate this concept further exist today. Due to the complex interaction between unsteady aerodynamics and movement of the floating structure fully coupled simulation tools, modelling both aero and structural dynamics are needed. A nonlinear Lifting Line Free Vortex Wake code was recently integrated into the open source wind turbine simulation suite QBlade. This paper describes some of the necessary adaptions of the algorithm, which differentiates it from the usual application in HAWT simulations. A focus is set on achieving a high robustness and computational efficiency. A short validation study compares simulation results with those of a URANS and a Double Multiple Streamtube (DMS) simulation.
http://isromacisimet.univlille1.fr/index.php?rubrique=abstract&num=24
ISROMAC 16
10.13140/RG.2.1.3116.5849
D.Marten
M.Lennie
C. N.Nayeri
C. O.Paschereit
incollection
Sieber2016
Identification of unstable coherent modes in reacting swirling flows and their control
2016
http://dx.doi.org/10.2514/6.20161840
American Institute of Aeronautics and Astronautics
AIAA SciTech
54th AIAA Aerospace Sciences Meeting
C. O. Paschereit, K. OberleithnerM. Sieber
inproceedings
Bölke2016
Akustische Charakterisierung tieffrequent modulierter NRPPlasmaentladungen und Kontrolle thermoakustischer Instabilitäten
2016
449  452
Thermoakustische Instabilitäten stellen noch immer eine hohe Herausforderung bei der Entwicklung moderner Verbrennungssysteme dar. Durch Kopplung von Wärme und Druckschwankungen werden teilweise so hohe Druckamplituden erzeugt, dass es zu Beschädigungen umliegender Strukturen kommen kann. Mittels passiver Maßnahmen als auch aktiver Kontrolle wird versucht, diesen Effekt abzuschwächen. Jüngste Arbeiten haben gezeigt, dass gepulste Nanosekunden (NRP) Plasmaentladungen zur Beeinflussung thermoakustischer Instabilitäten eingesetzt werden können. Hierbei wird sowohl auf thermischer, chemischer als auch akustischer Ebene das System beeinflusst. Zur Untersuchung der jeweiligen Einflussfaktoren wurden im Rahmen dieser Arbeit die Schallerzeugungsmechanismen für niederfrequent modulierte NRPEntladungen untersucht. Der Einfluss auf das akustische Feld beruht hierbei auf der kurzzeitigen Wärmefreisetzung der Entladungen. Zum Erzeugen einer maximalen tieffrequenten Schalldruckamplitude wurden mittels BurstModulation aus den einzelnen Entladungen periodische Signalformen erzeugt. Zur Bestimmung der akustischen Quellamplitude wurden Messungen auf Grundlage der MultiMikrofonMethode (MMM) im Impedanzrohr durchgeführt. Untersucht wurde der Einfluss der Modulationsfrequenz, der Pulswiederholrate, der Burst Dauer, des Elektrodenabstandes als auch der Umgebungstemperatur auf die erzeugte Schallleistung. Gemessen wurde zudem die elektrische Leistung der Entladungen. Durch Ausdruck der akustischen Quellamplitude in Abhängigkeit der instationären Wärmefreisetzungsrate ließ sich zudem auch der instantan in Wärme umgesetzte Energieanteil bestimmen. Des Weiteren wurden Untersuchungen zur Dämpfung thermoakustischer Instabilitäten am RijkeRohr durchgeführt.
1 DVDROM: Illustrationen
http://publications.rwthaachen.de/record/657934
Michael Vorländer, Janina Fels
RWTH Aachen  Institut für Technische Akustik
Fortschritte der Akustik: DAGA 2016
Berlin: Deutsche Gesellschaft für Akustik e.V. (DEGA)
Aachen
DAGA
14.  17. März 2016
9783939296102, 3939296104
1
O.Bölke
D.Lacoste
J. P.Moeck
inproceedings
Wassmer2016
An Acoustic TimeofFlight Approach for Unsteady Temperature Measurements: Characterization of Entropy Waves in a Model Gas Turbine Combustor
2016
ASME Paper GT201656571
Proceedings of ASME Turbo Expo 2016, June 1317, 2016, Seoul, South Korea
10.1115/GT201656571
D.Wassmer
B.Schuermans
C. O.Paschereit
J. P.Moeck
inproceedings
Kuhn_2016
Control of the precessing vortex core by open and closedloop forcing in the jet core
2016
Volume 4B: Combustion, Fuels and Emissions
13
The precessing vortex core (PVC) is the dominant coherent structure of swirling jets, which are commonly applied in gas turbine combustion. It stems from a global hydrodynamic instability that is caused by internal feedback mechanisms in the jet core. In this work, we apply open and closedloop forcing in a generic nonreacting jet to control this mechanism and the PVC. Control is exerted by two oppositely facing, counterphased zeronet mass flux jets, which are introduced radially into the flow through a thin lance positioned on the jet center axis. By using this type of forcing, the instability mode m = 1, corresponding to the PVC, can either be excited or damped. This markedly affects the PVC oscillation frequency and amplitude. The passive influence of the actuation lance on the mean flow field properties and the coherent flow dynamics is studied first without forcing. PIV and hotwire measurements reveal an effect on the mean flow, but no qualitative changes of the PVC dynamics. Lockin experiments are conducted, in which the synchronization behavior of the PVC with the forcing is determined. Here, two different cases are considered. First, actuation is applied at different streamwise positions in order to identify the region of highest receptivity towards external forcing. This region of lowest lockin amplitude is shown to coincide with the location of the wavemaker, shortly upstream of the vortex breakdown bubble. Second, the lockin behavior at a fixed axial position and various forcing frequencies ff is studied. A linear correlation between the lockin amplitude and the deviation of the forcing frequency from the natural oscillation frequency ff – fn is observed. Closedloop control is then applied with the aim to suppress the PVC. The actuator lance is positioned in the wavemaker region, where the flow is most receptive. Magnitude and phase of the natural flow oscillation associated with the PVC are estimated from four hotwire signals using an extended Kalman filter. The estimated PVC signal is phaseshifted and fed back to the actuator. PIV measurements reveal that feedback control achieves a reduction of the PVC oscillation energy of about 40 %.
Paper No. GT201657686, pp. V04BT04A036
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2555103
ASME
Proceedings of ASME Turbo Expo 2016, June 13  17, 2016, Seoul, South Korea
10.1115/GT201657686
P.Kuhn
J. P.Moeck
C. O.Paschereit
K.Oberleithner
inproceedings
Marten2016b
Effects of Airfoil's Polar Data in the Stall Region on the Estimation of Darrieus Wind Turbine Performance
2016
9
11
Interest in verticalaxis wind turbines (VAWTs) is experiencing a renaissance after most major research projects came to a standstill in the mid 90’s, in favour of conventional horizontalaxis turbines (HAWTs). Nowadays, the inherent advantages of the VAWT concept, especially in the Darrieus configuration, may outweigh their disadvantages in specific applications, like the urban context or floating platforms. To enable these concepts further, efficient, accurate, and robust aerodynamic prediction tools and design guidelines are needed for VAWTs, for which loworder simulation methods have not reached yet a maturity comparable to that of the Blade Element Momentum Theory for HAWTs’ applications. The two computationally efficient methods that are presently capable of capturing the unsteady aerodynamics of Darrieus turbines are the Double Multiple Streamtubes (DMS) Theory, based on momentum balances, and the Lifting Line Theory (LLT) coupled to a free vortex wake model. Both methods make use of tabulated lift and drag coefficients to compute the blade forces. Since the incidence angles range experienced by a VAWT blade is much wider than that of a HAWT blade, the accuracy of polars in describing the stall region and the transition towards the “thin plate like” behaviour has a large effect on simulation results. This paper will demonstrate the importance of stall and poststall data handling in the performance estimation of Darrieus VAWTs. Using validated CFD simulations as a baseline, comparisons are provided for a blade in VAWTlike motion based on a DMS and a LLT code employing three sets of poststall data obtained from a wind tunnel campaign, XFoil predictions extrapolated with the ViternaCorrigan model and a combination of them. The polar extrapolation influence on quasisteady operating conditions is shown and azimuthal variations of thrust and torque are compared for exemplary tipspeed ratios (TSRs). In addition, the major relevance of a proper dynamic stall model into both simulation methods is highlighted and discussed.
Paper No. GT201656685, pp. V009T46A007
http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2555663
Seoul, South Korea, June 13–17, 2016
Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy
ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition
ASMe
10.1115/GT201656685
D.Marten
A.Bianchini
G.Pechlivanoglou
F.Balduzzi
C. N.Nayeri
G.Ferrara
C. O.Paschereit
L.Ferrari
inproceedings
Strangfeld2016
High AdvanceRatio Airfoil Streamwise Oscillations: Wind Tunnel vs. Water Tunnel
2016
AIAA paper no. 2016
AIAA SciTech, 54th Aerospace Sciences Meeting, 48 January, San Diego, California, USA
D.Greenblatt
H.MuellerVahl
C.Strangfeld
A.Medina
M. V.Ol
inproceedings
Bölke2016b
Sound generation and control of thermoacoustic instabilities by nanosecond plasma discharges
2016
8
Sound generation by nanosecond repetitively pulsed plasma discharges is investigated experimentally. High voltage pulses of 10 nanosecond duration provide rapid heating of the air. Ahighfrequency pulse train between 20 and 30 kHz is burst modulated to generate lowfrequencycomponents. The generation of pressure waves from the modulated discharge pulse train is characterized based on acoustic measurements in an impedance tube. Different combinations of modulation frequency, electrode gap distance, modulation duty cycle and pulse repetition frequency are studied in terms of electric energy and acoustic source a plitude. The measurement results suggest that overall, the amplitude of the pressure wave components at the modulation frequency can be well estimated based on the electrical power using an a nalytical expression for acoustically compact unsteady heating. As an application of sound generation by lowfrequency modulated NRP discharges, feedback control is applied to suppress the rmoacoustic instabilities in a Rijke tube. The pressure oscillation amplitude is reduced by more than two orders of magnitude when the plasma discharges are suitably synchronized with the selfexcited fluctuations.
http://www.iiav.org/archives_icsv_last/2016_icsv23/content/papers/papers/full_paper_118_20160517105405844.pdf
Prof. Konstantinos Vogiatzis, Prof. Georges Kouroussis, Prof. Malcolm Crocker, Prof. Marek Pawelczyk
Proceedings of the 23rd International Congress on Sound and Vibration
International Institute of Acoustics and Vibration (IIAV)
9789609922623
23293675
1
O.Bölke
D.Lacoste
J.P.Moeck
article
Williams2015
Modeling lift hysteresis with a modified Goman_Khrabrov model on pitching airfoils
AIAA, Aerospace Research Central
2015
6
http://arc.aiaa.org/doi/pdfplus/10.2514/6.20152631
00011452
10.2514/MFD15
D. R.Williams
F.Reißner
D.Greenblatt
H.MuellerVahl
C.Strangefeld
article
Vahl2015c
Mixing enhancement of an axisymmetric jet using flaplets with zero massflux excitation
Experiments in Fluids
2015
2
56
38
Springer Berlin Heidelberg
07234864 (print), 14321114 (online)
10.1007/s003480141889z
H.MüllerVahl
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
article
Mushyam2015
A numerical investigation of laminar flow over a backward facing inclined step
Meccanica
2015
124
The aim of the present study is to analyze the two dimensional flow over a backwardfacinginclined step in laminar flow regime. The inspiration for the present work is derived from the fact that in automobile industry, analyzing the flow over an inclined step shall help in understanding the characteristics of the rear vehicle wake. A considerable percentage of the energy needed to propel the vehicle is dissipated by the vorticity generated in the rear of the vehicle, hence it is of utmost importance to understand the properties of the wake. In the present paper, the flow over a backward step is initially analyzed and the results are compared with the existing literature to validate the code developed. The inclined step simulations were carried out by varying different aspects of the geometry i.e. different tilts, several upstream lengths and a range of different Reynolds numbers. Critical Reynolds numbers for vortex shedding in the wake of different step inclinations have been analyzed for all cases studied. A discussion on the timeaveraged drag and lift coefficients as a function of Reynolds number and for all cases undertaken, are among the results presented. Among the conclusions, it is particularly interesting to point out that the inclination angle of 15{\textdegree} was found to be the critical angle for vortex shedding, after which critical Reynolds number remains constant.
http://dx.doi.org/10.1007/s1101201503355
15729648
10.1007/s1101201503355
A.Mushyam
J. M.Bergada
C. N.Nayeri
article
Schimek2015
AmplitudeDependent Flow Field and Flame Response to Axial and Tangential Velocity Fluctuations
Journal of Engineering for Gas Turbines and Power
2015
137
8
GTP141525
0815011/10
The current paper investigates the nonlinear interaction of the flow field and the unsteady heat release rate and the role of swirl fluctuations. The test rig consists of a generic swirlstabilized combustor fed with natural gas and equipped with a highamplitude forcing device. The influence of the phase between axial and azimuthal velocity oscillations is assessed on the basis of the amplitude and phase relations between the velocity fluctuations at the inlet and the outlet of the burner. These relations are determined in the experiment with the MultiMicrophoneMethod and a two component LaserDoppler velocimeter. Particle image velocimetry and OH*chemiluminescence measurements are conducted to study the interaction between the flow field and the flame. For several frequency regimes, characteristic properties of the forced flow field and flame are identified, and a strong amplitude dependence is observed. It is found that the convective time delay between the swirl generator and the flame has an important influence on swirlnumber oscillations and the flame dynamics in the lowfrequency regime. For mid and high frequencies, significant changes in the mean flow field and the mean flame position are identified for high forcing amplitudes. These affect the interaction between coherent structures and the flame and are suggested to be responsible for the saturation in the flame response at high forcing amplitudes.
http://gasturbinespower.asmedigitalcollection.asme.org/data/Journals/JETPEZ/0/GTP141525.pdf
10.1115/1.4029368
S.Schimek
B.Ćosić
J. P.Moeck
S.Terhaar
C. O.Paschereit
article
Kabiraj2015
Chaos in an imperfectly premixed model combustor
Chaos: An Interdisciplinary Journal of Nonlinear Science
2015
25
2

http://scitation.aip.org/content/aip/journal/chaos/25/2/10.1063/1.4906943
10.1063/1.4906943
L.Kabiraj
A.Saurabh
N.Karimi
A.Sailor
E.Mastorakos
A. P.Dowling
C. O.Paschereit
article
Nayeri2015
Collaborative research on wind turbine load control under realistic turbulent inflow conditions
DEWEK 2015
2015
Modern turbines control load and power by actively adjusting the angle of attack via pitch variation. However, this technology is not suited for compensating the inflow variations generated by the atmospheric boundary layer or from upstream wind turbines (wind farms) or yaw errors, sudden gusts or turbulence which can occur within seconds or less and can have local impact on a rotor blade. In a collaborative research effort of five German universities, passive and active flow control methods for the alleviation of dynamic loads, load fluctuations and for reduction of wake effects are investigated, both experimentally and numerically. Furthermore, numerical tools suitable for evaluating the overall cost reduction and benefit of flow control methods on wind turbines will be validated and extended such that the results can be transferred to fullscale wind turbines under realistic inflow conditions.
http://15.dewek.de/fileadmin/downloads/Book_of_Abstracts_2015.pdf
DEWI
C. N.Nayeri
S.Vey
D.Marten
G.Pechlivanoglu
C. O.Paschereit
article
Nayeri2015
Control of Thick Airfoil, Deep Dynamic Stall Using Steady Blowing
AIAA Journal
2015
53
2
277295
10.2514/1.J053090
H.MuellerVahl
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
article
Niether2015a
Development of a Fluidic Actuator for Adaptive Flow Control on a Thick Wind Turbine Airfoil
Journal of Turbomachinery
2015
137
6
061003 (10 pages)
http://asmedigitalcollection.asme.org/data/Journals/JOTUEI/0/TURBO141229.pdf
0889504X
10.1115/1.4028654
S.Niether
B.Bobusch
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
article
Marten2015
Implementation, Optimization, and Validation of a Nonlinear Lifting LineFree Vortex Wake Module Within the Wind Turbine Simulation Code QBLADE
Journal of Engineering for Gas Turbines and Power
2015
137
The development of the next generation of large multimegawatt wind turbines presents exceptional challenges to the applied aerodynamic design tools. Because their operation is often outside the validated range of current state of the art momentum balance models, there is a demand for more sophisticated, but still computationally efficient simulation methods. In contrast to the Blade Element Momentum Method (BEM) the Lifting Line Theory (LLT) models the wake explicitly by a shedding of vortex rings. The wake model of freely convecting vortex rings induces a timeaccurate velocity field, as opposed to the annular averaged induction that is computed from the momentum balance, with computational costs being magnitudes smaller than those of a full CFD simulation. The open source code QBlade, developed at the Berlin Institute of Technology, was recently extended with a Lifting Line  Free Vortex Wake algorithm. The main motivation for the implementation of a LLT algorithm into QBlade is to replace the unsteady BEM code AeroDyn in the coupling to FAST to achieve a more accurate representation of the unsteady aerodynamics and to gain more information on the evolving rotor wake and flowfield structure. Therefore, optimization for computational efficiency was a priority during the integration and the provisions that were taken will be presented in short. The implemented LLT algorithm is thoroughly validated against other benchmark BEM, LLT and panel method codes and experimental data from the MEXICO and NREL Phase VI tests campaigns. By integration of a validated LLT code within QBlade and its database, the setup and simulation of LLT simulations is greatly facilitated. Simulations can be run from already existing rotor models without any additional input. Example use cases envisaged for the LLT code include; providing an estimate of the error margin of lower fidelity
GTP151421
http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=2467296
Journal of Engineering for Gas Turbines and Power
10.1115/1.4031872
D.Marten
M.Lennie
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
incollection
Gray2015
An Experimental Study of Different Obstacle Types for Flame Acceleration and DDT
2015
127
265279
Rudibert King
Springer
Notes on Numerical Fluid Mechanics and Multidisciplinary Design
Active Flow and Combustion Control 2014
9783319119663
10.1007/9783319119670
J.Gray
C. O.Paschereit
J. P.Moeck
incollection
Greenblatt2015
Dielectric Barrier Discharge Plasma Flow Control on a Vertical Axis Wind Turbine
2015
127
7186
Rudibert King
Springer
Notes on Numerical Fluid Mechanics and Multidisciplinary Design
Active Flow and Combustion Control 2014
9783319119663
10.1007/9783319119670
D.Greenblatt
H.MüllerVahl
R.Lautman
A.BenHarav
B.Eshel
inproceedings
Lennie2015a
A Review of Wind Turbine Polar Data and its Effect on Fatigue Loads Simulation Accuracy
2015
ASME Paper GT201543249
V009T46A018 (13 pages)
Proceedings of ASME Turbo Expo 2015, June 1519, 2015, Montreal, Quebec, Canada
9780791856802
10.1115/GT201543249
M.Lennie
G.Pechlivanoglou
D.Marten
C. N.Nayeri
C. O.Paschereit
inproceedings
Schaepel2015a
Adaptive Control of Mixture Profiles for a Combustion Tube
2015
ASME Paper GT201542027
V04AT04A005 (12 pages)
Proceedings of ASME Turbo Expo 2015, June 1519, 2015, Montreal, Quebec, Canada
9780791856680
10.1115/GT201542027
J. S.Schäpel
R.King
B.Bobusch
J. P.Moeck
C. O.Paschereit
inproceedings
Marten2015a
Configuration and Numerical Investigation of the Adaptive Camber Airfoil as Passive Load Alleviation Mechanism for Wind Turbines
2015
AIAA paper no. 20153390
AIAA Aviation, 33rd AIAA Applied Aerodynamics Conference, June 2226, 2015, Dallas, Texas, USA
9781624103636
10.2514/6.20153390
D.Marten
H.Spiegelberg
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
T.Cameron
inproceedings
Gray2015a
Effect of initial flow velocity on the flame propagation in obstructed channels
2015
AIAA paper no. 20151351
AIAA SciTech, 53rd Aerospace Sciences Meeting, 59 January, Kissimmee, Florida, USA
10.2514/6.20151351
J.Gray
J. P.Moeck
C. O.Paschereit
inproceedings
Vey2015a
Experimental and Numerical Investigations of a Small Research Wind Turbine
2015
AIAA paper no. 20153392
AIAA Aviation, 33rd AIAA Applied Aerodynamics Conference, June 2226, 2015, Dallas, Texas, USA
9781624103636
10.2514/6.20153392
S.Vey
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Stoehr2015a
Experimental study of transient coupling of PVC formation and flame shape transition in a bistable turbulent swirl flame.
2015
Proceedings of the 7th European Combustion Meeting (ECM 2015), Budapest, Hungary
M.Stöhr
K.Oberleithner
C. M.Arndt
A. M.Steinberg
W.Meier
inproceedings
Marten2015a
Implementation, Optimization and Validation of a Nonlinear Lifting Line Free Vortex Wake Module Within the Wind Turbine Simulation Code QBlade
2015
ASME Paper GT201543265
V009T46A019 (11 pages)
Proceedings of ASME Turbo Expo 2015, June 1519, 2015, Montreal, Quebec, Canada
9780791856802
10.1115/GT201543265
D.Marten
M.Lennie
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Oberleithner2015c
Linear stability analysis of turbulent swirling combustor flows: impact of flow field and flame shapes on the PVC
2015
Proceedings of the 7th European Combustion Meeting (ECM 2015), Budapest, Hungary
M.Stöhr
K.Oberleithner
C. M.Arndt
A. M.Steinberg
W.Meier
inproceedings
Huang2015a
Numerical and Experimental Investigation of Wind Turbine Wakes
2015
AIAA paper no. 20152310
AIAA Aviation, 45th AIAA Fluid Dynamics Conference, June 2225, 2015, Dallas, Texas, USA
9781624103629
10.2514/6.20152310
X.Huang
S.Vey
M.Meinke
W.Schroeder
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Strangfeld2015b
Unsteady Thick Airfoil Aerodynamics: Experiments, Computation, and Theory
2015
AIAA paper no. 20153071
AIAA Aviation, 45th AIAA Fluid Dynamics Conference, June 2225, 2015, Dallas, Texas, USA
9781624103629
10.2514/6.20153071
C.Strangfeld
C. L.Rumsey
H.MüllerVahl
D.Greenblatt
C. N.Nayeri
C. O.Paschereit
article
Strangfeld2014b
Experimental Comparison of the Aerodynamic Behavior of Fastback and Notchback DrivAer Models
SAE Int. J. Passeng. Cars  Mech. Syst.
2014
7
2
2014010613
682691
http://papers.sae.org/2014010613/
Society of Automobile Engineers
SAE 2014 World Congress & Exhibition, October 2122, Detroit, Michigan, USA
10.4271/2014010613
D.Wieser
H.J.Schmidt
S.Müller
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
article
Cosic2014
Nonlinear Instability Analysis for Partially Premixed Swirl Flames
Combustion Science and Technology
2014
186
6
713736
http://www.tandfonline.com/doi/pdf/10.1080/00102202.2013.876420
00102202
10.1080/00102202.2013.876420
B.Ćosić
J. P.Moeck
C. O.Paschereit
article
Cosic2014aa
Response of a swirlstabilized flame to simultaneous perturbations in equivalence ratio and velocity at high oscillation amplitudes
Combustion and Flame
2014
162
4
1046–1062
in press
00102180
10.1016/j.combustflame.2014.09.025
B.Ćosić
S.Terhaar
J. P.Moeck
C. O.Paschereit
conference
Moennich2014
Investigation of the flow in an axial blood pump with the paint erosion method
2014
9
17
Rome, Italy
41st Annual ESAO Congress, European Society for Artificial Organs
Sep 1720, 2014
03913988
B.Mönnich
T.Karakaya
B.Blümel
K.Affeld
U.Kertzscher
conference
Moennich2014
Analysis of shear stress volumes in the HeartWare HVAD and Heartmate II
2014
San Francisco, CA, USA
22nd Annual Congress of the International Society of Rotary Blood Pumps (ISRBP)
Sep 2527, 2014
B.Mönnich
B.Blümel
J.Schaller
K.Affeld
U.Kertzscher
conference
Marten2014f
QBlade: open source wind turbine design
2014
http://www.igcschennai.org
Invited Talk, IGCS Workshop on Improving Energy Sustainability  Conventional and Renewable, Dec. 45, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India
D.Marten
incollection
Gray2015b
Nonreacting investigations of a pseudoorifice for the purpose of enhanced deflagration to detonation transition
2014
176181
International Conference on Pulsating and Continuous Detonations
Roy, G. D. and Frolov, S. M.
Torus Press
Combustion and Detonation Series
Transient Combustion and Detonation Phenomena:Fundamentals and Applications
J.Gray
J. P.Moeck
C. O.Paschereit
inproceedings
Strangfeld2014a
Airfoil subjected to highamplitude freestream oscillations: theory and experiments
2014
AIAA
7th AIAA Theoretical Fluid Mechanics Conference, 1620 June, Atlanta, GA, USA
9781624102936
0.2514/6.20142926
C.Strangfeld
H.MuellerVahl
D.Greenblatt
C. N.Nayeri
C. O.Paschereit
inproceedings
MuellerVahl2014
Control of Unsteady Aerodynamic Loads Using Adaptive Blowing
2014
AIAA
32nd AIAA Applied Aerodynamics Conference, 1620 June, Atlanta, GA, USA
9781624102882
10.2514/6.20142562
H.MuellerVahl
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
inproceedings
Matthew2014
Development and Validation of a Modal Analysis Code for Wind Turbine Blades
2014
ASME Paper GT201427151
V03BT46A031
Proceedings of ASME Turbo Expo 2014, June 1620, 2014, Düsseldorf, Germany
9780791845660
10.1115/GT201427151
L.Matthew
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Niether2014a
Development of a Fluidic Actuator for Adaptive Flow Control on a Thick Wind Turbine Airfoil
2014
ASME Paper GT201425922
V03BT46A018
http://asmedigitalcollection.asme.org/data/Conferences/ASMEP/80912/V03BT46A018GT201425922.pdf
Proceedings of ASME Turbo Expo 2014, June 1620, 2014, Düsseldorf, Germany
9780791845660
10.1115/GT201425922
S.Niether
B.Bobusch
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Saurabh2014a
Swirl Flame Response to Traveling Acoustic Waves
2014
ASME Paper GT201426829
V04BT04A043 (9 pages)
http://proceedings.asmedigitalcollection.asme.org/data/Conferences/ASMEP/80916/V04BT04A043GT201426829.pdf
Proceedings of ASME Turbo Expo 2014, June 1620, 2014, Düsseldorf, Germany
9780791845691
10.1115/GT201426829
A.Saurabh
R.Steinert
J. P.Moeck
C. O.Paschereit
inproceedings
Vahl2014
Thick Airfoil Deep Dynamic Stall
2014
2
3540
http://dx.doi.org/10.1007/9783642546969_6
Hölling, Michael and Peinke, Joachim and Ivanell, Stefan
Springer Berlin Heidelberg
Research Topics in Wind Energy
Wind Energy  Impact of Turbulence
English
9783642546952
10.1007/9783642546969_6
H.MuellerVahl
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
inproceedings
Pechlivanoglou2014a
Utilization of Modern Large Scale HAWT Blade Design Techniques for the Development of Small HAWT Blades
2014
ASME Paper GT201425309
V03BT46A005 (9 pages)
http://proceedings.asmedigitalcollection.asme.org/data/Conferences/ASMEP/80912/V03BT46A005GT201425309.pdf
Proceedings of ASME Turbo Expo 2014, June 1620, 2014, Düsseldorf, Germany
9780791845660
10.1115/GT201425309
G.Pechlivanoglou
G.Weinzierl
I.Masmanidis
C. N.Nayeri
T.Philippidis
C. O.Paschereit
article
Bobusch2013b
Optical Measurement of Local and Global Transfer Functions for Equivalence Ratio Fluctuations in a Turbulent Swirl Flame
Journal of Engineering for Gas Turbines and Power
2013
11
1
136
2
021506
07424795 (online), 15288919 (print)
10.1115/1.4025375
B.Bobusch
B.Ćosić
J. P.Moeck
C. O.Paschereit
article
LacosteMDLS2013
Effect of Nanosecond Repetitively Pulsed Discharges on the Dynamics of a SwirlStabilized Lean Premixed Flame
Journal of Engineering for Gas Turbines and Power
2013
8
30
135
10
101501 (7 pages)
07424795 (online), 15288919 (print)
10.1115/1.4024961
D. A.Lacoste
J. P.Moeck
D.Durox
C. O.Laux
T. S.Schuller
article
Marten2013c
qblade: an open source tool for design and simulation ofhorizontal and vertical axis wind turbines
International Journal of Emerging Technology and Advanced Engineering (IJETAE)
2013
2
3
special issue 3
264269
http://www.ijetae.com/files/Conference%20ICERTSD2013/IJETAE_ICERTSD_0213_41.pdf
2250–2459 (Online)
D.Marten
J.Wendler
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
article
Lacoste2012
Dynamic Response of a Weakly Turbulent LeanPremixed Flame to Nanosecond Repetitively Pulsed Discharges
Proceedings of the Combustion Institute
2013
34
2
32593266
10.1016/j.proci.2012.07.017
D. A.Lacoste
D. A.Xu
J. P.Moeck
C. O.Laux
article
LacosteMPL2013
Effect of Plasma Discharges on Nitric Oxide Emissions in a Premixed Flame
Journal of Propulsion and Power
2013
29
3
748751
American Institute of Aeronautics and Astronautics
07484658, EISSN: 15333876
10.2514/1.B34819
D. A.Lacoste
J. P.Moeck
C. O.Paschereit
C. O.Laux
article
Marten2013a
Energieeffiziente Gestaltung eines gemischten Forschungs und Gewerbe und Wohnquartiers am Beispiel Berlin Adlershof, Teil 7: Nutzung von Windenergie
GI  GebäudeTechnik  InnenraumKlima
2013
01
Deutscher Industrieverlag
2195643X
D.Marten
article
DuroxMBMVSC2013
Flame dynamics of a variable swirl number system and instability control
Combustion and Flame
2013
160
9
17291742
10.1016/j.combustflame.2013.03.004
D.Durox
J. P.Moeck
J.F.Bourgouin
P.Morenton
M.Viallon
T. S.Schuller
S.Candel
article
MoeckBDSC2013
Tomographic reconstruction of heat release rate perturbations induced by helical modes in turbulent swirl flames
Experiments in Fluids
2013
54
4
117
07234864 (print), 14321114 (online)
10.1007/s0034801314982
J. P.Moeck
J.F.Bourgouin
D.Durox
T. S.Schuller
S.Candel
conference
nawroth2013d
Experimental Investigation of the Noise Emitted from an Unconfined Premixed Flame
2013
Euromech Colloquium 546: Combustion Dynamics and Combustion Noise, May 1316, 2013, Menaggio, Italy
H.Nawroth
J. P.Moeck
C. O.Paschereit
conference
Gray2013c
Investigations of the Dynamics of a Propagating Flame using HighSpeed Imaging and Laser Sheet Tomography
2013
#193
Proceedings of the 24th International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS) 28 July  2 August 2013, Taipei, Taiwan (Republic of China)
J.Gray
J. P.Moeck
C. O.Paschereit
inproceedings
MoeckLLP2013
Control of combustion dynamics in a swirlstabilized combustor with nanosecond repetitively pulsed discharges
2013
AIAA paper no. 20130565
http://arc.aiaa.org/doi/pdfplus/10.2514/6.2013565
51st AIAA Aerospace Science Meeting, Grapevine, Texas, USA, Jan. 0710
10.2514/6.2013565
J. P.Moeck
D. A.Lacoste
C. O.Laux
C. O.Paschereit
inproceedings
Marten2013b
Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines
2013
ASME paper GT201394979
V008T44A017 (9 pages)
Proc. ASME Turbo Expo 2013, June 37, San Antonio, Texas, USA
9780791855294
10.1115/GT201394979
D.Marten
J.Wendler
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Lacoste2013
Effect of Nanosecond Repetitively Pulsed Discharges on the Dynamics of a SwirlStabilized Lean Premixed Flame
2013
ASME paper GT201394769
V01AT04A054 (9 pages)
Proc. ASME Turbo Expo 2013, June 37, San Antonio, Texas, USA
9780791855102
10.1115/GT201394769
D. A.Lacoste
J. P.Moeck
D.Durox
C. O.Laux
T. S.Schuller
inproceedings
nawroth2013b
Experimental Investigation of an Unconfined SwirlStabilized Turbulent Premixed Flame
2013
AIAA paper 20132601
American Institute of Aeronautics and Astronautics
43rd AIAA Fluid Dynamics Conference, June 2427, 2013, San Diego, California, USA
9781624102141
10.2514/6.20132601
H.Nawroth
K.Moriarty
J.Beuth
C. O.Paschereit
inproceedings
Bobusch2013c
Optical Measurement of Local and Global Transfer Functions for Equivalence Ratio Fluctuations in a Turbulent Swirl Flame
2013
ASME paper GT201395649
V01BT04A048 (12 pages)
Proc. ASME Turbo Expo 2013, June 37, San Antonio, Texas, USA
9780791855119
10.1115/GT201395649
B.Bobusch
B.Ćosić
J. P.Moeck
C. O.Paschereit
inproceedings
Cosic2013e
Prediction of Pressure Amplitudes of SelfExcited Thermoacoustic Instabilities for a Partially Premixed SwirlFlame
2013
ASME paper GT201394160
V01AT04A007 (11 pages)
Proc. ASME Turbo Expo 2013, June 37, San Antonio, Texas, USA
9780791855102
10.1115/GT201394160
B.Ćosić
J. P.Moeck
C. O.Paschereit
inproceedings
Marten2013
QBlade: An Open Source Tool for Design and Simulation of Horizontal and vertical Axis Wind Turbines
International Journal of Emerging Technology and Advanced Engineering, vol. 3, special issue 3
2013
http://www.ijetae.com/files/Conference%20ICERTSD2013/IJETAE_ICERTSD_0213_41.pdf
International Conference on Energy Resources and Technologies for Sustainable Development (ICERTSD), Bengal Engineering & Science University, Shibpur, Howrah, West Bengal, INDIA
ISSN 2250 – 2459 (Online)
D.Marten
J.Wendler
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Bourgouin2013
SelfSustained Instabilities in an Annular Combustor Coupled by Azimuthal and Longitudinal Acoustic Modes
2013
ASME paper GT201395010
V01BT04A007 (13 pages)
Proc. ASME Turbo Expo 2013, June 37, San Antonio, Texas, USA
9780791855119
10.1115/GT201395010
J.F.Bourgouin
D.Durox
J. P.Moeck
T. S.Schuller
S.Candel
inproceedings
Vahl2013
Thick Airfoil Deep Dynamic Stall and its Control
2013
AIAA paper no. 20130854
http://arc.aiaa.org/doi/pdfplus/10.2514/6.2013693
51st AIAA Aerospace Science Meeting, Grapevine, Texas, USA, Jan. 0710
10.2514/6.2013854
H.MuellerVahl
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
article
cosic:2012
OpenLoop Control of Combustion Instabilities and the Role of the Flame Response to TwoFrequency Forcing
Journal of Engineering for Gas Turbines and Power
2012
4
12
134
6
061502
http://link.aip.org/link/?GTP/134/061502/1
ASME
07424795 (online), 15288919 (print)
10.1115/1.4005986
B.Ćosić
B.Bobusch
J. P.Moeck
C. O.Paschereit
article
Gelbert2012
Advanced algorithms for gradient estimation in one and twoparameter extremum seeking controllers
Journal of Process Control
2012
22
4
700709
In extremum seeking control, the gradient estimation is the key enabler for a successful online optimization. For this purpose, the classical algorithm uses a combination of high and lowpass filters. In this investigation extended Kalman filters (EKF) are used instead. The approach is explained in detail and advantages of Kalman filtering will become apparent. A novel approach for the gradient estimation for dualinput singleoutput systems is presented. The proposed EKF incorporates the coupling of the output to both inputs, thus, enabling a superior gradient estimate. A simulation study shows that faster convergence of the extremumseeking controller can be achieved using this estimator. The feasibility of the proposed algorithm in an experimental setup is demonstrated by control of thermoacoustic instabilities in an atmospheric combustor test rig.
http://www.sciencedirect.com/science/article/pii/S0959152412000340
09591524
10.1016/j.jprocont.2012.01.022
G.Gelbert
J. P.Moeck
C. O.Paschereit
R.King
article
Gelbert2012a
Feedback control of unstable thermoacoustic modes in an annular Rijke tube
Control Engineering Practice
2012
20
8
770782
Simulation and experimental results from an annular Rijke tube are presented. This system is a thermoacoustic surrogate system of an annular gas turbine combustor which, despite its simplicity, possesses the basic mechanisms to feature unstable azimuthal modes. A thermoacoustic network model is set up and used to derive loworder models for modal control of the system. The derived controllers are successfully applied in simulation and experiment. With the modal controllers, all unstable acoustic modes can be eliminated individually. A simultaneous use of all controllers results in a complete stabilization of the system.
http://www.sciencedirect.com/science/article/pii/S0967066112000809
09670661
10.1016/j.conengprac.2012.03.016
G.Gelbert
J. P.Moeck
C. O.Paschereit
R.King
article
MoeckBDSC2012
Nonlinear interaction between a precessing vortex core and acoustic oscillations in a turbulent swirling flame
Combustion and Flame
2012
159
8
26502668
The interaction of a helical mode with acoustic oscillations is studied experimentally in a turbulent swirlstabilized premixed flame. In addition to a precessing vortex core (PVC), the helical mode features perturbations in the outer shear layer of the burner flow. Measurements of the acoustic pressure, unsteady velocity field and flame emission are made in different regimes including selfsustained combustion oscillations and stable regimes with and without acoustic forcing. The acoustic oscillation and the helical mode create a pronounced rotating heat release rate perturbation at a frequency corresponding to the difference of the frequencies of the two individual mechanisms. Measurements over a wide range of operating conditions for different flow rates and equivalence ratios show that while the helical mode is always present, with a constant Strouhal number, selfexcited thermoacoustic oscillations exist only in a narrow region. The interaction can be observed also in cases of thermoacoustically stable conditions when external acoustic modulation is applied to the system. The evolution of the helical mode with the forcing amplitude is examined. Highspeed imaging from the downstream side of the combustor demonstrates that the heat release rate perturbation associated with the nonlinear interaction of the helical mode and the acoustic oscillations produces a ”yin and yang” type pattern rotating with the interaction frequency in the direction of the mean swirl. At unstable conditions, the oscillation amplitude associated with the interaction is found to be significantly stronger in the heat release rate than in the velocity signal, indicating that the nonlinear interaction primarily occurs in the flame response and not in the aerodynamic field. The latter is, however, generally possible as is demonstrated under nonreacting conditions with acoustic forcing. Based on a secondorder analysis of the Gequation, it is shown that the nonlinear flame dynamics necessarily generate the observed interaction component if the flame is simultaneously perturbed by a helical mode and acoustic oscillations.
http://www.sciencedirect.com/science/article/pii/S0010218012001216
10.1016/j.combustflame.2012.04.002
J. P.Moeck
J.F.Bourgouin
D.Durox
T. S.Schuller
S.Candel
article
Moeck2012
Nonlinear interactions of multiple linearly unstable thermoacoustic modes
International journal of spray and combustion dynamics
2012
4
1
128
We investigate the dynamics of thermoacoustic systems with multiple linearly unstable modes. Ifa linear analysis reveals more than one mode with positive growth rate, nonlinear methods haveto be used to determine the existence and stability of steadystate oscillations. One possible wayto engage this problem is a firstorder harmonic balance approach based on describing functionrepresentations for the flame response. In contrast to the case of a single unstable mode, thenonlinearity output to multiple sinusoidal components with different frequencies and amplitudeshas to be known. Based on this approach, we present conditions for the existence and stability ofsingle or multimode steadystate oscillations. We apply this method to a thermoacoustic modelsystem having two linearly unstable modes. By varying one of the system parameters, we findstable and unstable singlemode steadystates as well as unstable simultaneous oscillations.Associated with the stability of the singlemode limit cycles, we identify hysteresis in theoscillation type. Some related experimental observations are discussed.
MultiScience Publishing
17568277
J. P.Moeck
C. O.Paschereit
article
Candel2012
Progress and challenges in swirling flame dynamics
Comptes Rendus Mécanique
2012
340
1112
758768
http://www.sciencedirect.com/science/article/pii/S163107211200188X
16310721
10.1016/j.crme.2012.10.024
S.Candel
D.Durox
T. S.Schuller
P.Palies
J.F.Bourgouin
J. P.Moeck
conference
Wendler2012
QBlade: OpenSource Horizontal and Vertical Axis Wind turbine Design and Simulation
2012
QBlade_poster.pdf
Renewable Energy 2030  Experts Visions, Carl von Ossietzky University, Oldenburg, Germany, 12 Oct.
J.Wendler
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
conference
Vahl2012b
Thick airfoil deep dynamic stall
2012
EUROMECH Colloquium 528  Wind Energy and the impact of turbulence on the conversion process, Oldenburg, Germany, 2224 Feb.
H.MuellerVahl
C.Strangfeld
C. N.Nayeri
C. O.Paschereit
D.Greenblatt
conference
Marten2012
Wind Turbine Design and Analysis & Micrositing for Small Wind Turbines in Urban Areas
2012
Summer School 2012  Meeting the Challenges of Advanced Energy Systems for the Futue, IndoGerman Center for Sustainability, Berlin, EUREF Campus, 14.07.2012
D.Marten
inproceedings
Schimek2012c
Amplitudedependent flow field and flame response to axial and tangential velocity fluctuations
2012
ASME paper GT201269785
13211333 (13 pages)
Proc. ASME Turbo Expo 2012, June 1115, Bella Center, Copenhagen, Denmark
9780791844687
10.1115/GT201269785
S.Schimek
B.Ćosić
J. P.Moeck
S.Terhaar
C. O.Paschereit
inproceedings
Moeck2012b
Investigation of precessingvortexcoreflame interaction based on tomographic reconstruction techniques
2012
ASME paper GT201269626
12131224 (12 pages)
Proc. ASME Turbo Expo 2012, June 1115, Bella Center, Copenhagen, Denmark
9780791844687
10.1115/GT201269626
J. P.Moeck
J.F.Bourgouin
D.Durox
T. S.Schuller
S.Candel
inproceedings
Schuller2012
Modeling the response of premixed flame transfer functions  Key elements and experimental proofs
2012
AIAA paper no. 20120985
http://arc.aiaa.org/doi/pdfplus/10.2514/6.2012985
50th AIAA Aerospace Science Meeting, Nashville, Tennessee, USA, Jan. 912
10.2514/6.2012985
T. S.Schuller
A.Cuquel
P.Palies
J. P.Moeck
D.Durox
S.Candel
inproceedings
Schroedinger2012b
Numerical studies on the influence of periodical flow forcing on mixing quality and flow structure of a swirl burner
2012
ASME paper GT201269843
13451356 (12 pages)
Proc. ASME Turbo Expo 2012, June 1115, Bella Center, Copenhagen, Denmark
9780791844687
10.1115/GT201269843
C.Schrödinger
J. P.Moeck
M.Oevermann
C. O.Paschereit
inproceedings
Bobusch2012
Thermoacoustic stability analysis of a kerosenefueled lean direct injection combustor employing acoustically and optically measured transfer matrices
2012
ASME paper GT201269034
781794 (14 pages)
Proc. ASME Turbo Expo 2012, June 1115, Bella Center, Copenhagen, Denmark
9780791844687
10.1115/GT201269034
B.Bobusch
J. P.Moeck
S.Sadig
C. O.Paschereit
inproceedings
Vahl2012
Vortex generators for wind turbine blades: a combined wind tunnel and wind turbine parametric study
2012
ASME paper GT201269197
899914 (16 pages)
Proc. ASME Turbo Expo 2012, June 1115, Bella Center, Copenhagen, Denmark
9780791844724
10.1115/GT201269197
H.MuellerVahl
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
article
schimek2011
An Experimental Investigation of the Nonlinear Response of an Atmospheric SwirlStabilized Premixed Flame
Journal of Engineering for Gas Turbines and Power
2011
4
25
133
10
101502 (7 pages)
Due to stringent emission restrictions, modern gas turbines mostly rely on lean premixed combustion. Since this combustion mode is susceptible to thermoacoustic instabilities, there is a need for modeling tools with predictive capabilities. Linear network models are able to predict the occurrence of thermoacoustic instabilities but yield no information on the oscillation amplitude. The prediction of the pulsation levels and hence an estimation whether a certain operating condition has to be avoided is only possible if information on the nonlinear flame response is available. Typically, the flame response shows saturation at high forcing amplitudes. A newly constructed atmospheric test rig, specifically designed for the realization of high excitation amplitudes over a broad frequency range, is used to generate extremely high acoustic forcing power with velocity fluctuations of up to 100% of the mean flow. The test rig consists of a generic combustor with a premixed swirlstabilized natural gas flame, where the upstream part has a variable length to generate adaptive resonances of the acoustic field. The OH* chemiluminescence response, with respect to velocity fluctuations at the burner, is measured for various excitation frequencies and amplitudes. From these measurements, an amplitude dependent flame transfer function is obtained. Phaseaveraged OH* pictures are used to identify changes in the flame shape related to saturation mechanisms. For different frequency regimes, different saturation mechanisms are identified.
http://link.aip.org/link/?GTP/133/101502/1
ASME
07424795 (online), 15288919 (print)
10.1115/1.4002946
S.Schimek
J. P.Moeck
C. O.Paschereit
inproceedings
Schimek2011c
Experimental investigation of the influence of high amplitude forcing and swirl fluctuations on the flow field and the transfer function of a swirlstabilized flame
2011
AIAA paper no. 20115702
47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, San Diego, California, Jul 31  Aug 3
S.Schimek
J. P.Moeck
C. O.Paschereit
inproceedings
Cosic2011
OpenLoop control of combustion instabilities and the role of the flame response to twofrequency forcing
2011
ASME paper GT201146503
Proc. ASME Turbo Expo 2011: Advancing Clean and Efficient Turbine Technology (GT2011), June 610, Vancouver, BC, Canada
B.Ćosić
B.Bobusch
J. P.Moeck
C. O.Paschereit
inproceedings
moeck2011
Unstable azimuthal modes in an annular Rijke tube: Dynamics and Control
2011
Proc. of the 18th International Congress on Sound and Vibration (ICSV), July 1014, Rio de Janeiro, Brazil
9788563243010 (CDROM
J. P.Moeck
C. O.Paschereit
article
Bothien2010
Comparison of Linear Stability Analysis with Experiments by Actively Tuning the Acoustic Boundary Conditions of a Premixed Combustor
Journal of Engineering for Gas Turbines and Power
2010
8
20
32
12
121502 (10 pages)
Linear stability analysis by means of loworder network models is widely spread in industry and academia to predict the thermoacoustic characteristics of combustion systems. Even though a vast amount of publications on this topic exist, much less is reported on the predictive capabilities of such stability analyses with respect to real system behavior. In this sense, little effort has been made on investigating if predicted critical parameter values, for which the combustion system switches from stability to instability, agree with experimental observations. Here, this lack of a comprehensive experimental validation is addressed by using a modelbased control scheme. This scheme is able to actively manipulate the acoustic field of a combustion test rig by imposing quasiarbitrary reflection coefficients. It is employed to continuously vary the downstream reflection coefficient of an atmospheric swirlstabilized combustion test rig from fully reflecting to anechoic. By doing so, the transient behavior of the system can be studied. In addition to that, an extension of the common procedure, where the stability of an operating point is classified solely based on the presence of high amplitude pressure pulsations and their frequency, is given. Generally, the predicted growth rates are only compared with measurements with respect to their sign, which obviously lacks a quantitative component. In contrast to that, in this paper, validation of linear stability analysis is conducted by comparing calculated and experimentally determined linear growth rates of unstable modes. Besides this, experimental results and model predictions are also compared in terms of frequency of the least stable mode. Excellent agreement between computations from the model and experiments is found. The concept is also used for active control of combustion instabilities. By tuning the downstream reflectivity of the combustion test rig, thermoacoustic instabilities can be suppressed. The underlying mechanism is an increase in the acoustic energy losses across the system boundary.
http://link.aip.org/link/?GTP/132/121502/1
ASME
07424795 (online), 15288919 (print)
10.1115/1.4000806
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Moeck2010
A ZeroMach Solver and Reduced Order Acoustic Representations for Modeling and Control of Combustion Instabilities
2010
4
108
291306
Thermoacoustic instabilities are a serious problem for lean premixed combustion systems. Due to different time and length scales associated with the flow field, combustion, and acoustics, numerical computations of thermoacoustic phenomena are conceptually challenging. Using these methods to successfully design active control strategies is therefore difficult. This work presents a coupled method for the simulation of thermoacoustic instabilities in low Mach number reacting flows. The acoustics are represented by an experimentally identified reduced order model. A zeroMach solver is used for the flame dynamics on the hydrodynamic scale. Two control schemes are employed to suppress thermoacoustic oscillations, equivalence ratio modulation and control of the acoustic boundary conditions. Both methods are shown to be capable of effectively diminishing the instability.
King, R.
SpringerVerlag Berlin
Notes on Numerical Fluid Mechanics and Multidisciplinary Design
Active Flow Control II, Papers Contributed to the Conference ''Active Flow Control II 2010'', Berlin, Germany, May 26 to 28, 2010
9783642117343 (print), 9783642117350 (online)
10.1007/9783642117350_19
J. P.Moeck
C.Scharfenberg
C. O.Paschereit
R.Klein
inproceedings
Lacarelle2010a
Modeling the fuel/air mixing to control the pressure pulsations and NOx emissions in a lean premixed combustor
2010
4
108
307321
This paper presents an overviewof the methodology developed to predict, control and optimize the NOx emissions and stability of lean premixed combustors. Investigations are performed firstly in cold flow and are validated with reacting flow measurements. A new cold flow mixing model describes the relevant characteristics of the fuel/airmixing, i.e. themixing quality and convective time delays, for different operating points of the system.Measurements in the combustor are performed to correct the flame position effect or calibrate the cold flowresults.The model is for the first time implemented in an extremum seeking controller to optimize the emissions and pressure pulsations of the combustor by adjusting the fuel mixing profile. A further increase of the fuel/air mixing, necessary for further NOx reductions, with pulsating fuel injection, is demonstrated. At the end, the developed adaptive control strategies demonstrate opportunities for future efficiency increases in industrial combustors.
King, Rudibert
SpringerVerlag Berlin
Notes on Numerical Fluid Mechanics and Multidisciplinary Design
Active Flow Control II, Papers Contributed to the Conference ''Active Flow Control II 2010'', Berlin, Germany, May 26 to 28, 2010
9783642117343 (print), 9783642117350 (online)
10.1007/9783642117350_20
A.Lacarelle
J. P.Moeck
C. O.Paschereit
G.Gelbert
R.King
D. M.Luchtenburg
B. R.Noack
J.Kasten
H. C.Hege
inproceedings
Singh2010
Active Control of an Incompressible Axisymmetric Jet using Flaps and Zero MassFlux Excitation
2010
AIAA paper no. 20104417
http://pdf.aiaa.org/preview/2010/CDReadyMFD10_2119/PV2010_4417.pdf
5th Flow Control Conference, 28 June  1 July, 2010, Chicago, Illinois, USA
Y.Singh
H.MuellerVahl
D.Greenblatt
C. N.Nayeri
C. O.Paschereit
inproceedings
Moeck2010a
Aktive Kontrolle thermoakustischer Instabilitäten in einem annularen Rijke Rohr
2010
Proc. DAGA 2010, Berlin, Germany
J. P.Moeck
G.Gelbert
M.Paul
C. O.Paschereit
R.King
inproceedings
Schimek2010
An Experimental Investigation of the Nonlinear Flame Response of an Atmospheric SwirlStabilized Premixed Flame
2010
ASME paper GT201022827
665675
http://link.aip.org/link/abstract/ASMECP/v2010/i43970/p665/s1
ASME
Proc. ASME Turbo Expo 2010: Power for Land, Sea, and Air (GT2010), June 14–18, Glasgow, Scotland
9780791843970
10.1115/GT201022827
S.Schimek
J. P.Moeck
C. O.Paschereit
inproceedings
Marten2010a
Integration of a WT Blade Design tool in XFOIL/XFLR5
2010
http://10.dewek.de/fileadmin/pdf/abstracts/S15_4.pdf
Proceedings of DEWEK 2010, 1718 November 2010, Bremen, Germany
D.Marten
G.Pechlivanoglou
C. N.Nayeri
C. O.Paschereit
inproceedings
Moeck2010b
Nonlinear Interactions of Multiple Linearly Unstable Thermoacoustic Modes
2010
Technische Universität München
Proceedings of the Int'l Summer School and Workshop on NonNormal and Nonlinear Effects in Aero and Thermoacoustics
J. P.Moeck
C. O.Paschereit
inproceedings
Lacarelle2010b
Scalar Mixing Enhancement In A Swirl Stabilized Combustor Trough Passive And Active Injection Control
2010
AIAA paper no. 20101332
http://pdf.aiaa.org/preview/2010/CDReadyMASM10_1812/PV2010_1332.pdf
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, Jan. 47, 2010, Orlando, Florida, USA
A.Lacarelle
L.Matho
C. O.Paschereit
inproceedings
Moeck2010c
Thermoacoustic Instabilities in an Annular Rijke tube
2010
ASME paper no. GT201023577
12191232
Thermoacoustic instabilities are a major concern in the design of gas turbine combustors. Most modern combustion chambers have an annular shape with multiple circumferentially arranged burners and, accordingly, suffer often from azimuthal instability modes. However, due to the complexity of a full annular system with a large number of burners, most experimental and numerical studies focus on single burner systems with essentially purely longitudinal acoustics. In the present work, we therefore introduce a thermoacoustic surrogate system — an annular Rijke tube — which, albeit its simplicity, possesses the basic mechanisms to feature unstable azimuthal modes. As in a conventional Rijke tube, the sources of mean and unsteady heat release in our setup are electrically driven heating grids. Different azimuthal instability modes are observed in the experiment, and the effect of two types of circumferential variations of the power input is investigated. A full suppression of the unstable modes is achieved by the application of an elementary feedback controller. The experimental investigations are accompanied by corresponding calculations with a loworder system model. Theoretical and experimental results are found to agree well.
http://link.aip.org/link/abstract/ASMECP/v2010/i43970/p1219/s1
ASME
Proc. ASME Turbo Expo 2010: Power for Land, Sea, and Air (GT2010), June 14–18, Glasgow, Scotland
9780791843970
10.1115/GT201023577
J. P.Moeck
M.Paul
C. O.Paschereit
article
Moeck2009
A twoway coupling for modeling thermoacoustic instabilities in a flat flame Rijke tube
Proceedings of the Combustion Institute
2009
32
1
11991207
Thermoacoustic instabilities are a serious problem for lean premixed combustion systems. Due to different time and length scales associated with the flow field, combustion, and acoustics, numerical computations of thermoacoustic phenomena are conceptually challenging. This work presents a coupled method for the simulation of thermoacoustic instabilities in low Mach number reacting flows. The acoustics are represented by a reduced order model that can be obtained from network techniques or finite element computations. A detailed chemistry finitedifference zero Mach number solver is used for the small scale flame dynamics. Under the assumption that the pressure is continuous across the flame, the acoustic model can be reduced to a timedomain relation mapping the velocity perturbation downstream of the flame to that upstream. Closure is obtained by the flame code, which delivers the jump in velocity across the combustion zone. The method is applied to an experimental laminar premixed burnerstabilized flat flame Rijke tube, that exhibits strong thermoacoustic oscillations associated with the 5λ/4 mode of the geometrical setup. In addition to the fundamental oscillation, a significant subharmonic response of the flame is observed. Results from the coupled simulation are compared to the experimental data. Good qualitative and quantitative agreement is found.
15407489
10.1016/j.proci.2008.05.062
J. P.Moeck
M.Oevermann
R.Klein
C. O.Paschereit
H.J.Schmidt
article
Bothien2009a
Assessment of different actuator concepts for acoustic boundary control of a premixed combustor
Journal of Engineering for Gas Turbines and Power
2009
131
2
021502 (10 pages)
http://link.aip.org/link/?GTP/131/021502/1
ASME
07424795 (online), 15288919 (print)
10.1115/1.2969088
M. R.Bothien
J. P.Moeck
C. O.Paschereit
article
Greenblatt2009
Flap vortex management using active Gurney flaps
AIAA Journal
2009
47
12
28452856
10.2514/1.41767
D.Greenblatt
S.Vey
C. O.Paschereit
R.Meyer
inproceedings
Schimek2009
Design of a combustion test rig with high amplitude forcing capabilities for nonlinear flame transfer function measurements
2009
M. Pawelczyk and D. Bismor (Hrsg.), 16th International Congress of Sound and Vibration, Krakov, Poland
9788360716717 (CDRom)
S.Schimek
J. P.Moeck
C. O.Paschereit
inproceedings
Lacarelle2009
Dynamic Mixing Model of a Premixed Combustor and Validation with Flame Transfer Function Measurements
2009
AIAA paper no. AIAA2009986
47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, Jan. 58, 2009, Orlando, Florida, USA
1563479699 (DVD)
A.Lacarelle
J. P.Moeck
A.Tenham
C. O.Paschereit
inproceedings
Bothien2009c
Experimental Validation of Linear Stability Analysis in a Premixed Combustor by Actively Tuning Its Acoustic Boundary Conditions
2009
Volume 2: Combustion, Fuels and Emissions
ASME paper GT200960019
787798
Linear stability analysis by means of loworder network models is widely spread in industry and academia to predict the thermoacoustic characteristics of combustion systems. Even though a vast amount of publications on this topic exists, much less is reported on the predictive capabilities of such stability analyses with respect to real system behaviour. In this sense, little effort has been made on investigating if predicted critical parameter values, for which the combustion system switches from stability to instability, agree with experimental observations. Here, this lack of a comprehensive experimental validation is addressed by using a modelbased control scheme. This scheme is able to actively manipulate the acoustic field of a combustion test rig by imposing quasi arbitrary reflection coefficients. It is employed to continuously vary the downstream reflection coefficient of an atmospheric swirlstabilized combustion test rig from fully reflecting to anechoic. By doing so, the transient behaviour of the system can be studied. In addition to that, an extension of the common procedure, where the stability of an operating point is classified solely based on the presence of high amplitude pressure pulsations and their frequency, is given. Generally, the predicted growth rates are only compared to measurements with respect to their sign, which obviously lacks a quantitative component. In contrast to that, in this paper, validation of linear stability analysis is conducted by comparing calculated and experimentally determined linear growth rates of unstable modes. Besides this, experimental results and model predictions are also compared in terms of frequency of the least stable mode. Excellent agreement between computations from the model and experiments is found. The concept is also used for active control of combustion instabilities. By tuning the downstream reflectivity of the combustion test rig, thermoacoustic instabilities can be suppressed. the underlying mechanism is an increase of the acoustic energy losses across the system boundary.
http://link.aip.org/link/abstract/ASMECP/v2009/i48838/p787/s1
Proc. ASME Turbo Expo 2009: Power for Land, Sea, and Air (GT2009), June 812, Orlando, Florida, USA
9780791838495 (CDROM), 9780791848838
10.1115/gt200960019
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Pfeifer2009
Localization of Sound Sources in Combustion Chamber
2009
XVIII
269291
Schwarz, A. and Janicka, J.
SpringerVerlag Berlin
Combustion Noise
9783642020377
C.Pfeifer
C. O.Paschereit
J. P.Moeck
L.Enghardt
inproceedings
Lacarelle2009a
Model Based Control of Emissions and Pulsations in a Premixed Combustor Using Fuel Staging
2009
Volume 2: Combustion, Fuels and Emissions
ASME paper GT200959300
217229
http://link.aip.org/link/abstract/ASMECP/v2009/i48838/p217/s1
Proc. ASME Turbo Expo 2009: Power for Land, Sea, and Air (GT2009), June 812, Orlando, Florida, USA
9780791848838
10.1115/gt200959300
A.Lacarelle
J. P.Moeck
C. O.Paschereit
G.Gelbert
R.King
inproceedings
Moeck2009a
Modeling thermoacoustic instabilities in an annular Rijke tube: Asymmetric and standing and spinning modes
2009
Proceedings of the 16th International Congress on Sound and Vibration, Krakow, Poland
9788360716717 (CDRom)
J. P.Moeck
C. O.Paschereit
inproceedings
Guyot2009a
Optical Transfer Function Measurement for a Premixed SwirlStabilized Flame at Atmospheric Conditions
2009
AIAA paper no. 20091236
47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, Jan. 58, 2009 , Orlando, Florida, USA
D.Guyot
J. P.Moeck
C. O.Paschereit
B.Schuermans
article
Bothien2008
Active Control of the Acoustic Boundary Conditions of Combustion Test Rigs
Journal of Sound and Vibration
2008
318
678701
0022460X
10.1016/j.jsv.2008.04.046
M. R.Bothien
J. P.Moeck
C. O.Paschereit
article
Pfeifer2008b
Localization of Sound Sources in Combustion Chambers
Acoustical Society of America Journal
2008
123
3405+
10.1121/1.2934112
C.Pfeifer
J. P.Moeck
L.Enghardt
C. O.Paschereit
inproceedings
DepuruMohan2008
Active and passive flow control of an incompressible axisymmetric jet
2008
Volume 6: Turbomachinery, Parts A, B, and C
ASME paper GT200850484
815827
ASME Turbo Expo 2008: Power for Land, Sea and Air, June 913, 2008, Berlin, Germany
9780791843161
10.1115/gt200850484
N. K. D.Mohan
D.Greenblatt
C. N.Nayeri
C. O.Paschereit
P. N.Ramamurthi
inproceedings
Greenblatt2008
Active management of flapedge trailing vortices
2008
paper No. AIAA 20084186
OnlineVer\"ffentlichung
Proc. 4th Flow Control Conference, Invited Paper, 2326 June 2008, Seattle, Washington, USA
9781563479427
D.Greenblatt
C. S.Yao
S.Vey
C. O.Paschereit
R.Meyer
inproceedings
Bothien2008a
Assessment of different actuator concepts for acoustic boundary control of a premixed combustor
2008
paper no. GT200850171
5769
In the design process, new burners are generally tested in combustion test rigs. With these experiments, computational fluid dynamics, and finite element calculations, the burners' performance in the fullscale engine is sought to be predicted. Especially, information about the thermoacoustic behavior and the emissions is very important. As the thermoacoustics strongly depend on the acoustic boundary conditions of the system, it is obvious that test rig conditions should match or be close to those of the fullscale engine. This is, however, generally not the case. Hence, if the combustion process in the test rig is stable at certain operating conditions, it may show unfavorable dynamics at the same conditions in the engine. In a previous paper (GT200727796), the authors introduced an active control scheme which is able to mimic almost arbitrary acoustic boundary conditions. Thus, the test rig properties can be tuned to correspond to those of the fullscale engine. The acoustic boundary conditions were manipulated using woofers. In the present study, proportional valves are investigated regarding their capabilities of being used in the control scheme. It is found that the test rig impedance can be tuned equally well. In contrast to the woofers, however, the valves could be used in industrial applications, as they are more robust and exhibit more control authority. Additionally, the control scheme is further developed and used to tune the test rig at discrete frequencies. This exhibits certain advantages compared to the case of control over a broad frequency band.
Proc. of GT2008, ASME Turbo Expo 2008: Power for Land, Sea and Air, 913 June 2008, Berlin, Germany
9780791843130 (online)
10.1115/GT200850171
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Vey2008
Flap vortex management by active Gurney flaps
2008
AIAA paper no. 20081058
OnlineVeröffentlichung
Proc. 46th AIAA Aerospace Sciences Meeting and Exhibit, 710 January 2008, Reno, Nevada, USA
1563479370
S.Vey
D.Greenblatt
C. O.Paschereit
R.Meyer
inproceedings
Pfeifer2008
Localization of combustion noise sources in enclosed flames
2008
2nd International Conference on Jets, Wakes and Separated Flows, Berlin, Sep 1619, 2008
C.Pfeifer
J. P.Moeck
L.Enghardt
C. O.Paschereit
inproceedings
Pfeifer2008a
Localization of sound sources in combustion chambers
2008
OnlineVeröffentlichung
34. Deutsche Jahrestagung für Akustik (DAGA 2008  Deutsche Arbeitsgemeinschaft für Akustik, Dresden, März 2008)
9782952110549
C.Pfeifer
J. P.Moeck
L.Enghardt
C. O.Paschereit
inproceedings
Pfeifer2008c
Lokalisierung von Schallquellen in geschlossenen Brennkammern
2008
34. Deutsche Jahrestagung für Akustik, Dresden, 1013 März, 2008
C.Pfeifer
J. P.Moeck
L.Enghardt
C. O.Paschereit
inproceedings
Gelbert2008
Model Predictive Control of Thermoacoustic Instabilities in a SwirlStabilized Combustor
2008
AIAA paper no. 20081055
46th AIAA Aerospace Sciences Meeting, 7  10 January 2008, Reno, Nevada
G.Gelbert
J. P.Moeck
M. R.Bothien
R.King
C. O.Paschereit
inproceedings
King2008
Model predictive flow control
2008
AIAA paper no. 20083975
38th Fluid Dynamics Conference and Exhibit, June 2326, 2008, Seattle, Washington, USA
1563479427
R.King
K.Aleksic
G.Gelbert
N.Losse
R.Muminovic
A.Brunn
W.Nitsche
M. R.Bothien
J. P.Moeck
C. O.Paschereit
B. R.Noack
U.Rist
M.Zengl
inproceedings
Moeck2008
Subcritical thermoacoustic instabilities in a premixed combustor
2008
paper no. 20082946
Proc. 14th AIAA/CEAS Aeroacoustics Conference, 57 May 2008, Vancouver, Canada
1563479397
J. P.Moeck
M. R.Bothien
S.Schimek
A.Lacarelle
C. O.Paschereit
article
Guyot2007
Active control of combustion instability using fuel flow modulation
Proceedings in Applied Mathematics and Mechanics (PAMM)
2007
7
1
40900154090016
10.1002/pamm.200700715
D.Guyot
M. R.Bothien
J. P.Moeck
C. O.Paschereit
article
Bothien2007b
Time domain modelling and stability analysis of complex thermoacoustic systems
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy
2007
221
5
657668
Professional Engineering
09576509 (Print) 20412967 (Onl
10.1243/09576509jpe384
M. R.Bothien
J. P.Moeck
A.Lacarelle
C. O.Paschereit
inproceedings
Moeck2007
An Active Control Scheme for Tuning Acoustic Impedances
2007
AIAA paper no. 20073540
13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference), May 2123, 2007, Rome, Italy
J. P.Moeck
M. R.Bothien
C. O.Paschereit
inproceedings
Moeck2007a
An assessment of alternative sensor technology for transfer matrix measurements in combustors
2007
Proceedings of the 14th International Congress on Sound and Vibration, 912 July 2007, Cairns, Australia
9780733425165
J. P.Moeck
H. J.Konle
C. O.Paschereit
inproceedings
Moeck2007b
An asymptotically motivated twoway hydrodynamicacoustic coupling for modeling thermoacoustic instabilities in a laminar flame Rijke tube
2007
Proceedings of the 14th International Congress on Sound and Vibration, 912 July 2007, Cairns, Australia
9780733425165
J. P.Moeck
H.J.Schmidt
M.Oevermann
C. O.Paschereit
R.Klein
inproceedings
Gutmark2007
Combustion Noise in a Flameless Trapped Vortex Reheat Burner (FTVRB)
2007
AIAA paper no. 20073697
13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference), May 2123, 2007, Rome, Italy
E. J.Gutmark
C. O.Paschereit
D.Guyot
A.Lacarelle
J. P.Moeck
S.Schimek
T.Faustmann
M. R.Bothien
inproceedings
Lacarelle2007
Effect of Fuel/Air Mixing on NOx Emissions and Stability in a Gas Premixed Combustion System
2007
AIAA paper no. 20071417
45th AIAA Aerospace Sciences Meeting and Exhibit, Jan. 811, 2007, Reno, Nevada, USA
A.Lacarelle
J. P.Moeck
H. J.Konle
S.Vey
C. N.Nayeri
C. O.Paschereit
inproceedings
Bothien2007
Experimental Validation of Linear Stability Analysis in Premixed Combustors Supported by Active Control
2007
Proceedings of the 14th International Congress on Sound and Vibration, Cairns, Australia
9780733425165
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Pfeifer2007
Identification of Combustion Noise Sources in Enclosed Flames
2007
11th CEAS/ASC Workshop of X3Noise, 27/28 September, 2007, Istituto Superior Tecnico, Lisbon
C.Pfeifer
J. P.Moeck
C. O.Paschereit
L.Enghardt
inproceedings
Bothien2007a
Impedance Tuning of a Premixed Combustor Using Active Control
2007
Volume 2: Turbo Expo 2007
ASME paper GT200727796
607617
ASME Turbo Expo 2007: Power for Land, Sea, and Air (GT2007), May 1417, 2007 , Montreal, Canada
0791847918
10.1115/gt200727796
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Paschereit2007
Leisere Busse
2007
20
638
Bundesministerium für Verkehr, Bau und Stadtentwicklung
VerkehrsblattVerlag, Bonn
Verkehrsblatt
00424013
C. O.Paschereit
J. P.Moeck
R.Engel
inproceedings
Moeck2007c
Passive Control of Combustion Induced Noise in an Auxiliary Bus Heating System
2007
Proceedings of the 14th International Congress on Sound and Vibration, Cairns, Australia
9780733425165
J. P.Moeck
R.Engel
C. O.Paschereit
inproceedings
Moeck2007d
PhaseShift Control of Combustion Instability Using (Combined) Secondary Fuel Injection and Acoustic Forcing
Notes on Numerical Fluid Mechanics and Multidisciplinary Design (NNFM)
2007
95
Papers contributed to the 1st Conference on "Active Flow Control", Sep. 2729, 2006, Berlin, Germany
408421
King, R.
SpringerVerlag Berlin
Notes on Numerical Fluid Mechanics and Multidisciplinary Design (NNFM)
9783540714385 und 35407143
10.1007/9783540714392
J. P.Moeck
M. R.Bothien
D.Guyot
C. O.Paschereit
inproceedings
Guyot2007b
Pollutant and Noise Emissions in a Flameless TrappedVortex Reheat Burner (FTVRB)
2007
AIAA paper no. 20075630
43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, July 811, 2007, Cincinnati, OH, USA
D.Guyot
M. R.Bothien
J. P.Moeck
A.Lacarelle
S.Schimek
T.Faustmann
C. O.Paschereit
E. J.Gutmark
inproceedings
Moeck2007e
TwoParameter Extremum Seeking for Control of Thermoacoustic Instabilities and Characterization of Linear Growth
2007
AIAA paper no. 20071416
Proc. 45th AIAA Aerospace Sciences Meeting and Exhibit, January 811, 2007, Reno, Nevada, USA
J. P.Moeck
M. R.Bothien
C. O.Paschereit
G.Gelbert
R.King
inproceedings
Bothien2006
A Modular Approach for Time Domain Modelling of Complex (Thermo)Acoustic Systems
2006
Proceedings of the 13th International Conference on Modelling Fluid Flow, Budapest, Hungary
M. R.Bothien
J. P.Moeck
C. O.Paschereit
inproceedings
Albrecht2006
Characterization and Control of Lean Blowout Using Periodically Generated Flame Balls
2006
Volume 1: Combustion and Fuels, Education
ASME paper GT200690340
293302
ASME Turbo Expo 2006: Power for Land, Sea, and Air (GT2006), May 811, 2006 , Barcelona, Spain
0791842363
10.1115/gt200690340
P.Albrecht
F.Bauermeister
M. R.Bothien
A.Lacarelle
J. P.Moeck
C. O.Paschereit
E. J.Gutmark
inproceedings
Schuermans2006
Nonlinear combustion instabilities in annular gasturbine combustors
2006
44th AIAA Aerospace Sciences Meeting and Exhibit, January 912, 2006, Reno, NV, USA
B.Schuermans
C. O.Paschereit
P.Monkewitz
inproceedings
Paschereit2006c
Statespace modeling of thermoacoustic systems for stability analysis and time domain simulation
2006
Vienna, Austria
Proceedings of the 13th International Congress on Sound and Vibration, July 26, 2006, Vienna, Austria
C. O.Paschereit
J. P.Moeck
M. R.Bothien
article
Paschereit2002b
Measurement of transfer matrices and source terms of premixed flames
Journal of Engineering for Gas Turbines and Power
2002
3
26
124
2
239247
07424795 (online), 15288919 (print)
10.1115/1.1383255
C. O.Paschereit
B.Schuermans
W.Polifke
O.Mattson
inproceedings
Bellucci2001
On the use of Helmholtz resonators for damping acoustic pulsations in industrial gas turbines
2001
ASME Turbo Expo, June 46, 2001, New Orleans, Louisiana, USA
V.Bellucci
C. O.Paschereit
P.Flohr
F.Magni
inproceedings
Paschereit1999e
Measurement of transfer matrices and source terms of premixed flames
1999
ASME Turbo Expo, June 710, 1999, Indianapolis, Indiana, USA
C. O.Paschereit
B.Schuermans
W.Polifke
O.Mattson