% % This file was created by the Typo3 extension % sevenpack version 0.7.16 % % --- Timezone: CET % Creation date: 2023-02-04 % Creation time: 00-42-25 % --- Number of references % 86 % @Article { Alber2020, title = {Aerodynamic effects of Gurney Flaps on the rotor blades of a research wind turbine}, journal = {Wind Energy Science}, year = {2020}, volume = {5}, number = {4}, pages = {1645--1662}, url = {https://wes.copernicus.org/articles/5/1645/2020/}, DOI = {10.5194/wes-5-1645-2020}, author = {Alber, J. and Soto-Valle, R. and Manolesos, M. and Bartholomay, S. and Nayeri, C. N. and Sch{\"o}nlau, M. and Menzel, C. and Paschereit, C. O. and Twele, J. and Fortmann, J.} } @Article { Noack_14092020, title = {Cluster-based network model}, journal = {Journal of Fluid Mechanics}, year = {2020}, volume = {906}, number = {21}, pages = {1-41}, abstract = {We propose an automatable data-driven methodology for robust nonlinear reduced-ordermodelling from time-resolved snapshot data. In the kinematical coarse-graining, 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 finite-time transitions. The transition probabilitiesand times are inferred from the snapshot data. The resulting cluster-based network modelconstitutes a deterministic-stochastic grey-box model resolving the coherent-structureevolution. This model is motivated by limit-cycle dynamics, illustrated for the chaoticLorenz attractor and successfully demonstrated for the laminar two-dimensional mixinglayer featuring Kelvin-Helmholtz vortices and vortex pairing, and for an actuatedturbulent boundary layer with complex dynamics. Cluster-based network modelling opensa promising new avenue with unique advantages over other model-order reductions basedon clustering or proper orthogonal decomposition.}, keywords = {low-dimensional models, shear layers, turbulent boundary layers}, url = {https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/clusterbased-network-model/8252D04A5438ED01E624A7C41CCF81BB}, DOI = {https://doi.org/10.1017/jfm.2020.785}, author = {Li, H. and Fernex, D. and Tan, J. and M., Morzynski and Noack, B. R.} } @Article { Tanneberger2020, title = {Heat transfer measurements in a hydrogen-oxyfuel combustor}, journal = {Experimental Heat Transfer}, year = {2020}, volume = {34}, number = {1}, pages = {20}, abstract = {In the context of emission-free electricity generation, the authors developed a novel hydrogen-oxygen combustor, which is based on swirl-stabilized combustion technology and steam dilution. Following previous burner characterization, the current study investigates the heat transfer conditions in the combustion chamber wall. To this end, a carefully controlled co-flow of air is used to cool the combustion chamber in an annular duct, which surrounds it. Temperature measurements enable the evaluation of the heat flux from the combustor flow to the walls, local wall temperatures, and the Nusselt numbers on the hot and the cold side. The extremely high wall temperatures, caused by the H2/O2 flame, can be reduced by steam dilution down to approximately 900 K. Even better cooling could be reached by using the dilution steam as the coolant before it flows to the plenum. The Nusselt numbers at the inner combustion chamber wall are in the order of 10-50 and increase with the thermal power and the steam dilution ratio.}, keywords = {Heat transferoxy-fuel combustionhydrogensteam dilution}, url = {https://doi.org/10.1080/08916152.2020.1798564}, DOI = {10.1080/08916152.2020.1798564}, author = {Tanneberger, T. and Stathopoulos, P.} } @Article { Noack_04112020, title = {Machine learning open-loop control of a mixing layer}, journal = {Physics of Fluids}, year = {2020}, volume = {32}, abstract = {We develop an open-loop control system using machine learning to destabilize and stabilize the mixing layer. The open-loop control law comprising harmonic functions is explored using the linear genetic programming in a purely data-driven and model-free manner. The best destabilization control law exhibits a square wave with two alternating duty cycles. The forced flow presents a 2.5 times increase in the fluctuation energy undergoing early multiple vortex-pairing. The best stabilization control law tames the mixing layer into pure Kelvin-Helmholtz vortices without following vortex-pairing. The 23 \% reduction of fluctuation energy is achieved under the dual high-frequency actuations.}, note = {111701}, url = {https://aip.scitation.org/doi/pdf/10.1063/5.0030071}, DOI = {https://doi.org/10.1063/5.0030071}, author = {Li, H. and Tan, J. and Gao, Z. and Noack, B. R.} } @Article { Noack_01092020, title = {On the cavity-actuated supersonic mixing layer downstream a thick splitter plate}, journal = {Physics of Fluids}, year = {2020}, volume = {32}, number = {9}, pages = {1-24}, abstract = {We propose a cavity as an actuator to actuate the supersonic mixing layer downstream a thick splitter plate. The cavity-actuated case at Re = 1.73 \(\times\) 105 is simulated using large eddy simulation. The forced dynamics is resolved by the cluster-based network model (CNM) from a probabilistic point of view. Introducing a cavity obtains a 50\% increase in the growth rate of vorticity thickness. The recirculation region immediately downstream the trailing edge of the splitter plate is largely reduced, which contributes to the advanced and fast growth of the redeveloping mixing layer. The cavity oscillation induces three-dimensional features that are beneficial to the small-scale mixing. Spectral analysis reveals that the cavity-actuated flow field exhibits the phenomena of the strict frequency-lock and temporal mode-switching. The CNM successfully resolves the intermittent dynamics of the supersonic mixing layer using only ten centroids. The CNM's outcomes reveal two flow regimes of the unforced case: the Kelvin-Helmholtz vortex and vortex pairing. The cavity oscillation significantly affects the flow patterns of the centroids, which exhibit flow structures closely associated with the wake mode and shear-layer mode of the cavity oscillations. The dynamics of the cavity-actuated case is tamed into a strictly periodic transition loop among ten clusters undergoing the cyclic motion of the cluster energy fluctuation from the maximum to the minimum. Each centroid of the cavity-actuated case transports much more turbulent kinetic energy than that of the unforced case. Overall, the cavity-actuated attractor gets a 3.27 times increase in the energy fluctuation.}, note = {096102}, url = {https://aip.scitation.org/doi/10.1063/5.0019299}, ISSN = {1070-6631}, DOI = {https://doi.org/10.1063/5.0019299}, author = {Tan, J. and Li, H. and Nock, B. R.} } @Article { Müller2020, title = {Receptivity of the turbulent precessing vortex core: Synchronization experiments and global adjoint linear stability analysis}, journal = {Journal of Fluid Mechanics}, year = {2020}, volume = {888}, pages = {A3}, url = {https://www.cambridge.org/core/product/identifier/S0022112019010632/type/journal\{\textbackslash_\}article}, publisher = {Cambridge University Press}, ISSN = {0022-1120}, DOI = {10.1017/jfm.2019.1063}, author = {M{\"u}ller, J. and L{\"u}ckoff, F. and Paredes, P. and Theofilis, V. and Oberleithner, K.} } @Inproceedings { rezay2020evaluation, title = {Evaluation of shock dividers using numerical and experimental methods}, year = {2020}, pages = {926}, url = {https://arc.aiaa.org/doi/10.2514/6.2020-0926}, publisher = {American Institute of Aeronautics and Astronautics}, address = {Reston, Virginia}, booktitle = {AIAA Scitech 2020 Forum}, ISBN = {978-1-62410-595-1}, DOI = {10.2514/6.2020-0926}, author = {Rezay Haghdoost, M. and Thethy, B. and Nadolski, M. and Klein, R. and Honnery, D. and Edgington-Mitchell, D. and Seo, B. and Paschereit, C. O. and Oberleithner, K.} } @Inproceedings { thethy2020redistribution, title = {Redistribution of transient shock waves using shock dividers}, year = {2020}, pages = {925}, url = {https://arc.aiaa.org/doi/10.2514/6.2020-0925}, publisher = {American Institute of Aeronautics and Astronautics}, address = {Reston, Virginia}, booktitle = {AIAA Scitech 2020 Forum}, ISBN = {978-1-62410-595-1}, DOI = {10.2514/6.2020-0925}, author = {Thethy, B. and Rezay Haghdoost, M. and Paschereit, C. O. and Honnery, D. and Edgington-Mitchell, D. and Oberleithner, Kilian} } @Article { Tschepe_2019, title = {Experimental investigation of the aerodynamic drag of roof-mounted insulators for trains}, journal = {IMechE}, year = {2019}, month = {8}, pages = {13}, abstract = {This paper presents the results of experimental investigations on the aerodynamic drag of roof-mounted insulators for use on low- and high-speed trains. Wind tunnel investigations at different Reynolds numbers in the subcritical, critical, and supercritical flow regime were performed, in addition to investigations using wall-mounted cylinders. Furthermore, the impact of insulator sheds made of flexible material was analyzed. For a better understanding of the aerodynamic behavior of the insulators when mounted on trains, different boundary conditions representing realistic configurations as found on the roof of trains were simulated. From the measured drag, the energy demand to overcome the aerodynamic resistance of different types of insulators was calculated. Depending on the above mentioned boundary conditions, a noticeable contribution of the insulators to the entire train's aerodynamic drag could be observed. With flexible insulator sheds, a further increased air resistance was observed with the onset of fluttering. Similar to the cylinder, the aerodynamic behavior of the insulators depends on the respective Reynolds number.}, url = {https://journals.sagepub.com/doi/10.1177/0954409719867537}, DOI = {10.1177/0954409719867537}, author = {J., Tschepe and T.-J., Maa{\ss} and C. N., Nayeri and C. O., Paschereit} } @Article { Tschepe2019_1, title = {Analysis of moving model experiments in a towing tank for aerodynamic drag measurement of high-speed trains}, journal = {Springer}, year = {2019}, pages = {16}, abstract = {The present study assesses the applicability of towing tank experiments using a moving model for the investigation of the aerodynamics of long land-borne heavy vehicles such as buses, trucks, and trains. Based on experiments with a 1:22 scaled model of a high-speed train, the influence of various conditions relevant for the transferability of the results obtained in water to air is analysed exemplarily. These conditions include surface waves, cavitation and submergence depth. The experiments were carried out in the shallow water towing tank of the Technische Universit{\"a}t Berlin. It is shown that outside a critical Froude number range of about 0.2 < Fr < 1.2 the impact of the surface waves can be neglected and no cavitation appears in the velocity range investigated. Furthermore, a correction method is proposed taking into account the bias through surface waves at small submergence and thus allowing for a wider Froude number range. The data obtained in the towing tank are found to be in excellent agreement to other investigation methods.}, url = {https://link.springer.com/article/10.1007/s00348-019-2748-8}, language = {English}, ISSN = {0723-4864}, DOI = {10.1007/s00348-019-2748-8}, author = {Tschepe, J. and Nayeri, C. N. and Paschereit, C. O.} } @Article { Tanneberger2019, title = {Combustion efficiency measurements and burner characterization in a hydrogen-oxyfuel combustor}, journal = {International Journal of Hydrogen Energy}, year = {2019}, keywords = {Oxy-fuel combustion, Hydrogen, Steam dilution, Combustion efficiency, Large scale energy storage}, url = {http://www.sciencedirect.com/science/article/pii/S0360319919318865}, ISSN = {0360-3199}, DOI = {https://doi.org/10.1016/j.ijhydene.2019.05.055}, author = {Tanneberger, T. and Schimek, S. and Paschereit, C. O. and Stathopoulos, P.} } @Article { Tanneberger_2019, title = {Efficiency Measurement Approach for a Hydrogen Oxyfuel Combustor}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2019}, volume = {141}, number = {10}, url = {https://doi.org/10.1115/1.4044779}, ISSN = {0742-4795}, DOI = {10.1115/1.4044779}, author = {Tanneberger, T. and Schimek, S. and Paschereit, C. O. and Stathopoulos, P.} } @Article { Holst2019, title = {Experimental analysis of a NACA 0021 airfoil section through 180-deg angle of attack at low Reynolds numbers for use in wind turbine analysis}, journal = {ASME}, year = {2019}, volume = {141}, number = {4}, pages = {12}, abstract = {Wind turbine industry has a special need for accurate post stall airfoil data. While literature often covers incidence ranges [−10 deg, +25 deg], smaller machines experience a range of up to 90 deg for horizontal axis and up to 360 deg for vertical axis wind turbines (VAWTs). The post stall data of airfoils is crucial to improve the prediction of the start-up behavior as well as the performance at low tip speed ratios. The present paper analyzes and discusses the performance of the symmetrical NACA 0021 airfoil at three Reynolds numbers (Re = 100 k, 140 k, and 180 k) through 180 deg incidence. The typical problem of blockage within a wind tunnel was avoided using an open test section. The experiments were conducted in terms of surface pressure distribution over the airfoil for a tripped and a baseline configuration. The pressure was used to gain lift, pressure drag, moment data. Further investigations with positive and negative pitching revealed a second hysteresis loop in the deep post stall region resulting in a difference of 0.2 in moment coefficient and 0.5 in lift.}, note = {GTP-18-1576}, keywords = {Airfoils, Pressure, Reynolds number, Wind turbines, Experimental analysis, Wind tunnels, Drag (Fluid dynamics)}, url = {https://doi.org/10.1115/1.4041651}, language = {English}, DOI = {10.1115/1.4041651}, author = {Holst, D. and Church, B. and Pechlivanoglu, G., and T{\"u}z{\"u}ner, E. and Saverin, J. and Nayeri, C. N. and Paschereit, C. O.} } @Article { Tschepe'2019, title = {Investigation of high-speed train drag with towing tank experiments and CFD}, journal = {Chalmers Research Publications}, year = {2019}, volume = {102}, pages = {417 - 434}, abstract = {In order to assess the accuracy of drag prediction methods for high-speed trains, experimental and numerical investigations were performed. Besides the drag coefficient, skin friction and pressure distributions on and near the model have been measured for a 1:22 model of the ICE/V. For the experiments, a moving model rig called DIWA (Drag measurement in water) was realised in a 120 m long towing tank to allow for a realistic simulation of the flow around the train, even in the underbelly region. Numerical investigations were performed using Partially-averaged Navier-Stokes (PANS) simulations based on the k-\(\omega\)-SST turbulence model. Both experimental and numerical methods can be considered as a novelty in the field of train aerodynamics. The results are compared with data from full-scale tests. It is shown, that the moving model rig DIWA allows for the measurement of drag coefficients of trains with high accuracy. Furthermore, the data acquired using the PANS approach compares well with the experimental data.}, keywords = {Towing tank, Train aerodynamics, Drag measurement, PANS, Moving model}, url = {https://research.chalmers.se/en/publication/510116}, ISSN = {1386-6184}, DOI = {10.1007/s10494-018-9962-y}, author = {Tschepe, J. and Fischer, D. and Nayeri, C. N. and Paschereit, C. O. and Krajnovic, S.} } @Article { Bartholomay_2018, title = {Cross-Talk compensation for blade root flap- and edgewise moments on an experimental research wind turbine and comparison to numerical results}, journal = {Proceedings of he ASME Turbo Expo 2018}, year = {2018}, volume = {9 Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy}, number = {GT2018-76977, pp. V009T48A016}, pages = {11}, abstract = {In the current paper a method to correct cross-talk effects for strain-gauge measurements is presented. The method is demonstrated on an experimental horizontal axis wind turbine. The procedure takes cross-moments (flap-wise 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 medium-fidelity code Qblade for a baseline case and two yawed inflow situations.}, note = {Oslo, Norway, June 11 - 15, 2018}, url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleID=2701583}, editor = {Bartholomay S., Marten D., S{\'a}nchez Martinez M., Alber J., Pechlivanoglou G., Nayeri C. N., Paschereit C. O., Klein A, Lutz Th. and Kr{\"a}mer E.}, series = {ASME Turbo Expo 2018}, organization = {ASME}, ISBN = {978-0-7918-5118-0}, DOI = {10.1115/GT2018-76977}, author = {Bartholomay, S. and Marten, D. and S{\'a}nchez Martinez, M. and Alber, J. and Pechlivanoglou, G. and Nayeri, C. N. and Paschereit, C. O. and Klein, A. C. and Thorsten, L. and Kr{\"a}mer, E.} } @Article { Reichel_2017, title = {Flashback prevention in lean-premixed hydrogen combustion Vermeidung von Flammenr{\"u}ckschlag in mager vorgemischter Verbrennung von Wasserstoff}, year = {2017}, month = {12}, pages = {108}, abstract = {The focus of this study is the combustion of hydrogen in air as it relates to typical gas turbine engines. Hydrogen-air combustion occurs in the absence of any carbon-based emissions and the only combustion products are water vapor and oxides of nitrogen (NOx). However, due to the very low flammability limit of hydrogen, it can be burned at much lower equivalence ratios than typical hydrocarbon fuels, resulting in excellent low NOx potential. Lean premixed combustion of low reactivity fuels, such as natural gas, is nowadays state of the art in stationary gas turbines. In the long term, it is also a promising approach for aero engines. For lean premixed combustion, with increasing fuel reactivity lean blow out limits are extended but the disposition for flashback, an undesired event of upstream flame propagation, is increased. Therefore, combustor design strategies that are applied for conventional fuels have to be revisited in case of hydrogen, which represents the upper end of the scale of high reactivity fuels. The current thesis aims at developing a combustor design that is capable of safely operating on hydrogen-air mixtures up to stoichiometric conditions while meeting strict emission regulations. To this end, several measures affecting the flashback resistance of a hydrogen-air combustor are investigated. In addition to their effect on flashback resistance, all measures are evaluated with respect to their impact on fuel-air mixing which directly affects NOx emissions. Unlike most previous investigations on hydrogen-air combustion, the current investigations are conducted at partially premixed instead of perfectly premixed conditions. This poses a challenging task with respect to achieving flashback resistance as well as low \textbackslashmathrm\{NO\(_{x\}}\) emissions with limited premixing space and time. Experimental investigation of non-reacting and reacting combustor flow fields of a partially premixed model combustor were conducted using particle image velocimetry in an atmospheric combustor tests rig. Results reveal a strong influence of geometric modifications and fuel momentum on the combustor flow field. Stability maps were recorded that allow for comparison of the operational range of different combustor geometries with respect to flashback and lean blow out. It was shown that already moderate flow rates of a central non-swirling air jet significantly extend the flashback limits, while the lean blow out limits remained unaffected. Moreover, recordings of planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) within the flame revealed that, the axial location of the upstream flame front, x\(_{f}\), constitutes a telling estimator for flashback resistance. At the investigated conditions, x\(_{f}\) is shifted downstream with increasing equivalence ratio due to the added momentum of the fuel flow. Thereby, the local gain in axial velocity due to fuel momentum supersedes any parallel augmentation in the turbulent flame speed. This has been identified as a driving mechanism affecting the combustor stability limit.Performance and emissions data facilitate the conclusion that the desired flashback-safe operation at very low NOx emissions at ambient pressure and relevant combustor inlet temperatures is feasible. Der Fokus dieser Arbeit liegt auf der experimentellen Untersuchung von Ma{\ss}nahmen zur Gew{\"a}hrleistung der sicheren und schadstoffarmen Verbrennung von Wasserstoff mit Luft in einer Gasturbine. Die Verbrennung von Wasserstoff mit Luft geschieht ohne den Aussto{\ss} jeglicher Kohlenwasserstoffe, sodass sich das Abgas ausschlie{\ss}lich aus Wasserdampf und Stickoxiden zusammensetzt. Der Stickoxidanteil kann dabei auf ein Minimum begrenzt werden da Wasserstoff aufgrund seiner weiten Z{\"u}ndgrenzen extrem mager verbrannt werden kann. Mager vorgemischte Verbrennung, wie sie heutzutage bereits in station{\"a}ren Gasturbinen zum Standard geh{\"o}rt, stellt mittelfristig auch einen vielversprechenden Ansatz f{\"u}r Fluggasturbinen dar. Der Einsatz hochreaktiver Brennstoffe, zum Beispiel wasserstoffreiche Synthesegase oder reiner Wasserstoff, erweitert zwar einerseits deutlich den mageren Betriebsbereich. Andererseits erh{\"o}ht sich auch enorm das Risiko des Auftretens von Flammenr{\"u}ckschlag, welcher zu massiver Besch{\"a}digung von Bauteilen f{\"u}hren kann. Die konventionellen Konzepte der Brennerentwicklung m{\"u}ssen daher f{\"u}r hochreaktive System neu gedacht werden, insbesondere f{\"u}r die Verbrennung von reinem Wasserstoff, der das obere Ende der Skala hochreaktiver Gasturbinentreibstoffe darstellt. Im Rahmen dieser Doktorarbeit wird der Einfluss verschiedener Ma{\ss}nahmen zur Vermeidung von Flammenr{\"u}ckschlag auf das nicht-reagierende und reagierende Str{\"o}mungsfeld experimentell untersucht. Dar{\"u}ber hinaus werden die Auswirkungen dieser {\"A}nderungen des Str{\"o}mungsfeldes auf die Flammenstabilisierung mit Hilfe moderner optischer Messtechnik gezeigt. Die daraus gewonnenen Erkenntnisse verm{\"o}gen die Beobachtungen der gemessenen Stabilit{\"a}tskarten zu erkl{\"a}ren. Durch die Identifikation von Indikatoren f{\"u}r Flammenr{\"u}ckschlag lassen sich au{\ss}erdem Voraussagen f{\"u}r die Stabilit{\"a}t jenseits des experimentell bestimmten Betriebsbereichs treffen. Im Rahmen der Untersuchungen stellte sich insbesondere das St{\"o}rungsfreie Einbringen des hohen Brennstoffimpulses als kritische Ma{\ss}nahme zur Wahrung von Flammenr{\"u}ckschlagsicherheit heraus. Weiterhin wurde gezeigt das verschiedene Ma{\ss}nahmen zur Vermeidung von Flammenr{\"u}ckschlag interagieren und teilweise interferieren. Es konnte jedoch gezeigt werden dass die vorgeschlagene Kombination der Ma{\ss}nahmen in der Brennergeometrie in der Lage ist Flammenr{\"u}ckschlag auf dem gesamten Betriebsbereich der Versuchsanlage zu verhindern und gleichzeitig ambitionierte Emissionsziele zu erf{\"u}llen.}, url = {https://depositonce.tu-berlin.de//handle/11303/7254 http://dx.doi.org/10.14279/depositonce-6530}, institution = {Technische Universit{\"a}t Berlin}, type = {phdthesis}, language = {English}, author = {Reichel, T. G. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Alber2017, title = {Parametric investigation of Gurney Flaps for the use on wind turbine blades}, year = {2017}, month = {8}, day = {17}, pages = {10}, abstract = {This paper presents a strategy to model the aerodynamic Gurney flap effect on two-dimensional airfoils and subsequently on the rotor blade performance of horizontal axis wind turbines.The first part consists of the parametric investigation of 26 airfoil polar data-sets, derived from different, but comparable, wind tunnel experiments. They are evaluated and processed in terms of the lift and drag increase caused by Gurney flaps in comparison to each Baseline configuration. Consequently, a model is developed, transforming Baseline- into Gurney flap polar data for varying flap-heights. The results of the emerging Gurney Flap Polar Calculator are validated against the experimental lift and drag curves.In the second part, the blade design of the NREL 5 MW Reference Turbine is modified by implementing polar data-sets of varying Gurney flap-heights, which are imported into the rotor simulation software QBlade. Thereupon, blade optimization strategies are examined regarding the two main Gurney flap applications on rotor blades: the retrofit and the design solution. The optimized retrofit solution on existing blades indicates power performance improvements, albeit at the expense of increasing structural loads. The optimized design solution on to-be-constructed blades, on the other hand, suggests chord-length reductions, while keeping the performance characteristics on a similar or even enhanced level.It is concluded that aerodynamic improvements are achieved by relatively small Gurney flap-heights, which are applied at specific blade positions.}, keywords = {Blades, Wind turbines, Design, Rotors, Airfoils, Drag (Fluid dynamics), Chords (Trusses), Computer software, Horizontal axis wind turbines, Optimization, Performance characterization, Simulation, Stress, Turbines, Wind tunnels}, url = {https://doi.org/10.1115/GT2017-64475}, booktitle = {ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition}, ISBN = {978-0-7918-5096-1}, author = {Alber, J. and Pechlivanoglou, G. and Paschereit, C. O. and Twele, J. and Weinzierl, G.} } @Inproceedings { Holst2017, title = {Experimental Analysis of a NACA 0021 Airfoil Section Through 180-Degree Angle of Attack at Low Reynolds Numbers for Use in Wind Turbine Analysis}, year = {2017}, month = {6}, day = {30}, volume = {9}, pages = {12}, abstract = {Wind turbine industry has a special need for accurate post stall airfoil data. While literature often covers incidence ranges [−10deg,+25deg] smaller machines experience a range of up to 90 deg for horizontal axis and up to 360 deg for vertical axis wind turbines (VAWTs). The post stall data of airfoils is crucial to improve the prediction of the start-up behavior as well as the performance at low tip speed ratios. The present paper analyzes and discusses the performance of the symmetrical NACA 0021 airfoil at three Reynolds numbers (Re = 100k, 140k, and 180k) through 180 deg incidence. The typical problem of blockage within a wind tunnel was avoided using an open test section. The experiments were conducted in terms of surface pressure distribution over the airfoil for a tripped and a baseline configuration. The pressure was used to gain lift, pressure drag, moment data. Further investigations with positive and negative pitching revealed a second hysteresis loop in the deep post stall region resulting in a difference of 0.2 in moment coefficient and 0.5 in lift.}, url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2650571}, publisher = {ASME}, series = {Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy}, booktitle = {ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition}, organization = {ASME}, event_place = {Charlotte, North Carolina, USA}, event_name = {ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition}, event_date = {26 - 30 Juni 2017}, language = {English}, ISBN = {ISBN: 978-0-7918-5096-1}, DOI = {10.1115/GT2017-63643}, author = {Holst, D. and Church, B. and Pechlivanoglou, G. and T{\"u}z {\"U}ner, E. and Saverin, J. and Nayeri, C. N. and Paschereit, C. O.} } @Article { Schuele2016, title = {Experimental and Numerical Investigation of an Axial Rotary Blood Pump}, journal = {Artificial Organs}, year = {2016}, month = {4}, editor = {Paul S. Malchesky}, organization = {International Federation for Artificial Organs}, ISSN = {1525-1594}, DOI = {10.1111/aor.12725}, author = {Sch{\"u}le, C. Y. and Thamsen, B. and Bl{\"u}mel, B. and Lommel, M. and Karakaya, T. and Paschereit, C. O. and Affeld, K. and Kertzscher, U.} } @Article { Stathopoulos2016b, title = {Emissions of a wet premixed flame of natural gas and a mixture with hydrogen at high pressure}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2016}, volume = {139}, number = {4}, pages = {8}, url = {http://gasturbinespower.asmedigitalcollection.asme.org/issue.aspx?journalid=120\&issueid=935804}, publisher = {ASME}, author = {Stathopoulos, P. and Kuhn, P. and Wendler, J. and Tanneberger, T. and Terhaar, S. and Paschereit, C. O. and Schmalhofer, C. and Griebel, P. and Aigner, M.} } @Inbook { Holst2016c, title = {Entwicklung eines aerodynamischen Pr{\"u}fstands zur Fl{\"u}gelprofiluntersuchung von Kleinwindkraftanlagen unter dynamischen Winkel{\"a}nderungen auf Basis eines cRiO-9068}, year = {2016}, pages = {54 - 57}, url = {http://sine.ni.com/cs/app/doc/p/id/cs-17418}, editor = {Rahman J., Heinze R.,}, publisher = {VDE Verlag}, edition = {Begleitband zum 21. VIP-Kongress}, chapter = {Mess-, Pr{\"u}f- und Regelungstechnik in Virtuelle Instrumente in der Praxis 2016}, ISBN = {978-3-8007-4441-1}, author = {Holst, D. and Thommes, K. and Sch{\"o}nlau, M. and Nayeri, C. N. and Paschereit, C. O.} } @Incollection { Nayeri2016b, title = {The Influence of Wind Tunnel Grid Turbulence on Aerodynamic Coefficients of Trains}, year = {2016}, volume = {79}, pages = {133-141}, editor = {Dillmann, A. and Orellano, A.}, publisher = {Springer International Publishing}, series = {Lecture Notes in Applied and Computational Mechanics}, booktitle = {The Aerodynamics of Heavy Vehicles III}, language = {English}, ISBN = {978-3-319-20121-4}, DOI = {10.1007/978-3-319-20122-1_8}, author = {Nayeri, C. N. and Strangfeld, C. and Zellmann, C. and Schober, M. and Tietze, A. and Paschereit, C. O.} } @Inproceedings { rw2016:tschepe, title = {Cross-Flow Induced Pressure on Air Outlets}, year = {2016}, abstract = {This paper shows that the interaction of an air stream (jet) coming from the outlet of a vehicle with the surrounding flow has an important impact on the pressure distribution in the outlet duct. Based on experimental investigations carried out in a wind tunnel it is shown that this interaction in most cases causes an additional counter pressure that has to be overcome by the acting fan. Depending on the parameter setting pressure differences in the order of several hundred Pascal can appear. Here, the most important parameter for this interaction turned out to be the momentum flux ratio of exhaust jet and cross-flow. This ratio is a result of the streams' fluid densities and velocities and is strongly affected by the near wall flow profile of the cross-flow upstream the outlet. Furthermore, the impact of geometry parameters such as the jet's exit shape is demonstrated.}, note = {paper 44}, url = {http://dx.doi.org/10.4203/ccp.110.44}, editor = {Pombo, J.}, publisher = {Civil-Comp Press}, address = {Stirlingshire, United Kingdom}, booktitle = {The Third International Conference on Railway Technology: Research, Development and Maintenance}, ISSN = {1759-3433}, DOI = {10.4203/ccp.110.44}, reviewed = {1}, author = {Tschepe, J. and Weise, M. and Tietze, A. and Nayeri, C. N. and Paschereit, C. O.} } @Inproceedings { Stathopoulos2016a, title = {Emissions of a wet premixed flame of natural gas and a mixture with hydrogen at high pressure}, year = {2016}, volume = {Volume 4B: Combustion, Fuels and Emissions}, pages = {11}, abstract = {It is generally accepted that combustion of hydrogen and natural gas mixtures will become more prevalent in the near future, to allow for a further penetration of renewables in the European power generation system. The current work aims at the demonstration of the advantages of steam dilution, when highly reactive combustible mixtures are used in a swirl-stabilized combustor. To this end, high-pressure experiments have been conducted with a generic swirl-stabilized combustor featuring axial air injection to increase flashback safety. The experiments have been conducted with two fuel mixtures, at various pressure levels up to 9 bar and at four levels of steam dilution up to 25 \% steam-to-air mass flow ratio. Natural gas has been used as a reference fuel, whereas a mixture of natural gas and hydrogen (10 \% hydrogen by mass) represented an upper limit of hydrogen concentration in a natural gas network with hydrogen enrichment. The results of the emissions measurements are presented along with a reactor network model. The latter is applied as a means to qualitatively understand the chemical processes responsible for the observed emissions and their trends with increasing pressure and steam injection.}, note = {Paper No. GT2016-57745, pp. V04BT04A040}, url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2555107\&resultClick=3}, publisher = {ASME}, booktitle = {Proceedings of ASME Turbo Expo 2016, June 13-17, 2016, Seoul, South Korea}, DOI = {10.1115/GT2016-57745}, author = {Stathopoulos, P. and Kuhn, P. and Wendler, J. and Tanneberger, T. and Terhaar, S. and Paschereit, C. O. and Schmalhofer, C. and Griebel, P. and Aigner, M.} } @Inproceedings { rw2016:tschep2, title = {Towing Tank Experiments for Train Aerodynamics}, year = {2016}, abstract = {This paper gives an overview on different experimental methods for the measurement of the aerodynamic drag of railroad vehicles in general as well as on the measurement of drag of submerged bodies in water in particular. It is shown that water based drag measurements with moving railroad models are very promising in terms of overcoming disadvantages in wind tunnel testing with scaled models. For this reason, a test setup in the water towing tank of the Technical University of Berlin is being developed to adapt the physical boundary conditions including high Reynolds numbers for more accurate results and the possibility to investigate full length model train compositions. Advantages and limitations of these experiments in water are discussed and preliminary results are presented.}, note = {paper 49}, url = {http://dx.doi.org/10.4203/ccp.110.49}, editor = {Pombo, J.}, publisher = {Civil-Comp Press}, address = {Stirlingshire, United Kingdom}, booktitle = {The Third International Conference on Railway Technology: Research, Development and Maintenance}, ISSN = {1759-3433}, DOI = {10.4203/ccp.110.49}, reviewed = {1}, author = {Tschepe, J. and Nayeri, C. N. and Schmidt, H.-J. and Paschereit, C. O.} } @Article { Cosic2014bb, title = {Acoustic response of Helmholtz dampers in the presence of hot grazing flow}, journal = {Journal of Sound and Vibration}, year = {2015}, volume = {335}, pages = {1-18}, ISSN = {0022-460X}, DOI = {/10.1016/j.jsv.2014.08.025}, author = {\'{C}osi\'{c}, B. and Wassmer, D. and Terhaar, S. and Paschereit, C. O.} } @Article { Schimek2015, title = {Amplitude-Dependent Flow Field and Flame Response to Axial and Tangential Velocity Fluctuations}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2015}, volume = {137}, number = {8}, number2 = {GTP-14-1525}, pages = {081501-1/10}, abstract = {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 swirl-stabilized combustor fed with natural gas and equipped with a high-amplitude 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 Multi-Microphone-Method and a two component Laser-Doppler 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 swirl-number oscillations and the flame dynamics in the low-frequency 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.}, url = {http://gasturbinespower.asmedigitalcollection.asme.org/data/Journals/JETPEZ/0/GTP-14-1525.pdf}, DOI = {10.1115/1.4029368}, author = {Schimek, S. and \'{C}osi\'{c}, B. and Moeck, J. P. and Terhaar, S. and Paschereit, C. O.} } @Article { Paredes2015b, title = {Global and Local Hydrodynamic Stability Analysis as a Tool for Combustor Dynamics Modeling}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2015}, number2 = {GTP-15-1320}, publisher = {ASME}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4031183}, author = {Paredes, P. and Theofilis, V. and Terhaar, S. and Oberleithner, K. and Paschereit, C. O.} } @Article { Reichel2015c, title = {Increasing Flashback Resistance in Lean Premixed Swirl-Stabilized Hydrogen Combustion by Axial Air Injection}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2015}, volume = {137}, number = {7}, number2 = {GTP-14-1522}, pages = {071503 (9 pages)}, DOI = {10.1115/1.4029119}, author = {Reichel, T. G. and Terhaar, S. and Paschereit, C. O.} } @Article { Terhaar2015b, title = {Investigation of the Global Mode in Swirling Combustor Flows: Experimental Observations and Local and Global Stability Analysis}, journal = {Procedia IUTAM}, year = {2015}, volume = {14}, pages = {553 - 562}, note = {IUTAM_ABCM Symposium on Laminar Turbulent Transition}, keywords = {Turbulent swirling flow}, url = {http://www.sciencedirect.com/science/article/pii/S2210983815001054}, ISSN = {2210-9838}, DOI = {10.1016/j.piutam.2015.03.079}, author = {Terhaar, S. and Paredes, P. and Oberleithner, K. and Theofilis, V. and Paschereit, C. O.} } @Article { TerhaarOP2014, title = {Key parameters governing the precessing vortex core in reacting flows: An experimental and analytical study}, journal = {Proceedings of the Combustion Institute}, year = {2015}, volume = {35}, number = {3}, pages = {3347-3354}, ISSN = {15407489}, DOI = {10.1016/j.proci.2014.07.035}, author = {Terhaar, S. and Oberleithner, K. and Paschereit, C. O.} } @Article { Thamsen2015, title = {Numerical analysis of blood damage potential of the Heartmate II and Heartware HVAD rotary blood pumps}, journal = {Artificial Organs (International Society for Artificial Organs, ISAO)}, year = {2015}, volume = {39}, number = {8}, pages = {651--659}, keywords = {Blood trauma, Left ventricular assist devices, Rotary blood pumps, Computational fluid dynamics, Blood damage}, ISSN = {1525-1594}, DOI = {10.1111/aor.12542}, author = {Thamsen, B. and Bl{\"u}mel, B. and Schaller, J. and Paschereit, C. O. and Affeld, K. and Goubergrits, L. and Kertzscher, U.} } @Article { Terhaar2014c, title = {Vortex Breakdown Types and Global Modes in Swirling Combustor Flows with Axial Injection}, journal = {Journal of Propulsion and Power}, year = {2015}, volume = {31}, number = {1}, pages = {219-229}, DOI = {10.2514/1.B35217}, author = {Terhaar, S. and Reichel, T. G. and Schr{\"o}dinger, C. and Rukes, L. and Oberleithner, K. and Paschereit, C. O.} } @Conference { Thamsen2015b, title = {Numerical Analysis of Hemolysis in the Heartmate II and Heartware HVAD Left Vectricular Assist Devices}, year = {2015}, month = {6}, day = {14}, event_place = {Lucca, Italy}, event_name = {Gordon Research Conference on Assisted Circulation}, event_date = {14-19 June 2015}, author = {Thamsen, B. and Bl{\"u}mel, B. and Schaller, J. and Affeld, K. and Kertzscher, U.} } @Inproceedings { Bluemel2015, title = {Modellierung der Blutsch{\"a}digung in Rotationsblutpumpen mit Eulerschem Ansatz in ANSYS CFX}, year = {2015}, month = {6}, day = {25}, booktitle = {Proceedings of 33th ANSYS Conference \& CADFEM Users Meeting, Jun 24-26, Bremen, Germany}, event_place = {Bremen, Germany}, event_name = {ANSYS Conference \& 33th CADFEM Users Meeting}, event_date = {June 24-26, 2015}, ISBN = {3-937523-12-X}, author = {Bl{\"u}mel, B. and Paschereit, C. O. and Thamsen, B. and Schaller, J.} } @Inproceedings { Schimek2015c, title = {Blue Combustion: Stoichiometric Hydrogen-Oxygen Combustion Under Humidified Conditions}, year = {2015}, number = {ASME Paper GT2015-43149}, pages = {V04BT04A007 (7 pages)}, booktitle = {Proceedings of ASME Turbo Expo 2015, June 15-19, 2015, Montreal, Quebec, Canada}, ISBN = {978-0-7918-5669-7}, DOI = {10.1115/GT2015-43149}, author = {Schimek, S. and Stathopoulos, P. and Tanneberger, T. and Paschereit, C. O.} } @Inproceedings { Kuhn2015a, title = {Design and Assessment of a Fuel-Flexible Low Emission Combustor for Dry and Steam-Diluted Conditions}, year = {2015}, number = {ASME Paper GT2015-43375}, pages = {V04BT04A024 (11 pages)}, booktitle = {Proceedings of ASME Turbo Expo 2015, June 15-19, 2015, Montreal, Quebec, Canada}, ISBN = {978-0-7918-5669-7}, DOI = {10.1115/GT2015-43375}, author = {Kuhn, P. and Terhaar, S. and Reichel, T. G. and Paschereit, C. O.} } @Inproceedings { Paredes2015a, title = {Global and Local Hydrodynamic Stability Analysis as a Tool for Combustor Dynamics Modeling}, year = {2015}, number = {ASME Paper GT2015-44173}, pages = {V04BT04A070 (10 pages)}, booktitle = {Proceedings of ASME Turbo Expo 2015, June 15-19, 2015, Montreal, Quebec, Canada}, ISBN = {978-0-7918-5669-7}, DOI = {10.1115/GT2015-44173}, author = {Paredes, P. and Theofilis, V. and Terhaar, S. and Oberleithner, K. and Paschereit, C. O.} } @Inproceedings { Tanneberger2015a, title = {Numerical Investigation of the Flow Field and Mixing in a Swirl-Stabilized Burner With a Non-Swirling Axial Jet}, year = {2015}, number = {ASME Paper GT2015-43382}, pages = {V04BT04A026 (12 pages)}, booktitle = {Proceedings of ASME Turbo Expo 2015, June 15-19, 2015, Montreal, Quebec, Canada}, ISBN = {978-0-7918-5669-7}, DOI = {10.1115/GT2015-43382}, author = {Tanneberger, T. and Reichel, T. G. and Kr{\"u}ger, O. and S., Terhaar and Paschereit, C. O.} } @Article { PaschereitTCO2014, title = {Application of linear hydrodynamic stability analysis to reacting swirling combustor flows}, journal = {Journal of Fluid Science and Technology}, year = {2014}, volume = {9}, number = {3}, pages = {1-14}, url = {https://www.jstage.jst.go.jp/article/jfst/9/3/9_2014jfst0024/_pdf}, DOI = {10.1299/jfst.2014jfst0024}, author = {Paschereit, C. O. and Terhaar, S. and \'{C}osi\'{c}, B. and Oberleithner, K.} } @Article { TerhaarKP2014, title = {Flow Field and Flame Dynamics of Swirling Methane and Hydrogen Flames at Dry and Steam-Diluted Conditions}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2014}, volume = {137}, number = {4}, pages = {041503 (10 pages)}, url = {http://gasturbinespower.asmedigitalcollection.asme.org/data/Journals/JETPEZ/931032/gtp_137_04_041503.pdf}, ISSN = {0742-4795}, DOI = {10.1115/1.4028392}, author = {Terhaar, S. and Kr{\"u}ger, O. and Paschereit, C. O.} } @Article { Terhaar2014, title = {Impact of shear flow instabilities on the magnitude and saturation of the flame response}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2014}, volume = {136}, number = {7}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84894523472\&partnerID=40\&md5=e5e37c408d2911b049f5a071dbcfaed7}, publisher = {ASME}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4026530}, author = {Terhaar, S. and \'{C}osi\'{c}, B. and Paschereit, C. O. and Oberleithner, K.} } @Article { Terhaar2014a, title = {Impact of Steam-Dilution on the Flame Shape and Coherent Structures in Swirl-Stabilized Combustors}, journal = {Combustion Science and Technology}, year = {2014}, volume = {186}, pages = {889-911}, abstract = {AbstractHumidified gas turbines and steam-injected gas turbines are promising technologies to lower the emissions and increase the efficiency and fuel flexibility of gas turbines. In the current study, the influence of steam-dilution on swirl-stabilized methane and hydrogen-fired flames is experimentally investigated at Reynolds numbers in the range of 22,000 to 32,000. Velocity fields and flame positions were measured using high-speed particle image velocimetry and OH* chemiluminescence. An extension of the quantitative light sheet technique was employed to estimate the temperature fields. The combined results reveal strong changes in the flame position, the velocity field, and the temperature field with increasing rates of steam dilution. In particular, three different flow and flame patterns are encountered: At dry conditions, a V-shaped flame stabilizes in a broad inner recirculation zone with low local turbulent kinetic energy; at moderate steam content, the flame changes into a trumpet-like shape; and at very high rates of steam-dilution, the flame detaches and shows an annular shape. The associated coherent flow structures are extracted from the PIV data employing proper orthogonal decomposition. The isothermal flow is dominated by a helical instability arising near the combustor inlet. This structure is completely suppressed for the dry flame and reappears for the heavily steam-diluted detached flame with similar shape and frequency as for the isothermal case. The flow field of the trumpet-like flame at intermediate to high steam dilution rates features a helical instability of lower frequency that is located further downstream than in the isothermal and very wet case. A conceptional explanation is presented that relates the suppression of the helical instability to the specific encountered temperature fields and flame shapes.}, url = {http://www.tandfonline.com/eprint/WaarDIijpj9TcDDGM7Xk/full}, DOI = {10.1080/00102202.2014.890597}, author = {Terhaar, S. and Oberleithner, K. and Paschereit, C. O.} } @Article { GokeSTRGKFGP2014, title = {Influence of Pressure and Steam Dilution on NOx and CO Emissions in a Premixed Natural Gas Flame}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2014}, volume = {139}, number = {091508}, pages = {1-8}, url = {http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=1838118\&resultClick=1}, ISSN = {0742-4795}, DOI = {10.1115/1.4026942}, author = {G{\"o}ke, S. and Schimek, S. and Terhaar, S. and Reichel, T. G. and G{\"o}ckeler, K. and Kr{\"u}ger, O. and Fleck, J. and Griebel, P. and Paschereit, C. O.} } @Article { Kruger2014, title = {Large eddy simulations of methane oxidation at ultra-wet conditions in a model gas turbine combustor applying detailed chemistry}, journal = {Journal of Fluid Science and Technology}, year = {2014}, volume = {9}, number = {3}, pages = {1--12}, DOI = {10.1299/jfst.2014jfst0040}, author = {Kr{\"u}ger, O. and Duwig, C. and Terhaar, S. and Paschereit, C. O.} } @Article { Goeckeler2013c, title = {Residence Time Distribution in a Swirling Flow at Nonreacting, Reacting, and Steam-Diluted Conditions}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2014}, volume = {136}, number = {4}, pages = {041505 (12 pages)}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4026000}, author = {G{\"o}ckeler, K. and Terhaar, S. and Paschereit, C. O.} } @Article { Cosic2014aa, title = {Response of a swirl-stabilized flame to simultaneous perturbations in equivalence ratio and velocity at high oscillation amplitudes}, journal = {Combustion and Flame}, year = {2014}, volume = {162}, number = {4}, pages = {1046-1062}, note = {in press}, ISSN = {0010-2180}, DOI = {10.1016/j.combustflame.2014.09.025}, author = {\'{C}osi\'{c}, B. and Terhaar, S. and Moeck, J. P. and Paschereit, C. O.} } @Conference { Wassmer2014, title = {Acoustic Response of Helmholtz Dampers in the Presence of Hot Grazing Flow}, year = {2014}, url = {http://www.efmc10.org/images/pdf/TIRSDAG_SAMLET_web.pdf}, booktitle = {10th European Fluid Mechanics Conference (EFMC10), Technical University of Denmark (DTU Lyngby), Copenhagen, 14-18 September}, author = {Wassmer, D. and \'{C}osi\'{c}, B. and Terhaar, S. and Paschereit, C. O.} } @Conference { Stathopoulos2014, title = {The ultra-wet cycle for high efficiency, low emission gas turbines}, year = {2014}, booktitle = {European Turbine Network ETN: The Future of Gas Turbine Technology, 7th IGTC, Brussels, Belgium, Oct. 14-15}, author = {Stathopoulos, P. and Terhaar, S. and Schimek, S. and Paschereit, C. O.} } @Inproceedings { TerhaarKP2014_2, title = {Flow Field and Flame Dynamics of Swirling Methane and Hydrogen Flames at Dry and Steam-Diluted Conditions}, year = {2014}, number = {ASME Paper GT2014-27023}, booktitle = {Proceedings of ASME Turbo Expo 2014, June 16-20, 2014, D{\"u}sseldorf, Germany}, author = {Terhaar, S. and Kr{\"u}ger, O. and Paschereit, C. O.} } @Inproceedings { ReichelTP2014, title = {Increasing Flashback Resistance in Lean Premixed Swirl-Stabilized Hydrogen Combustion by Axial Air Injection}, year = {2014}, number = {ASME Paper: GT2014-27002}, booktitle = {Proceedings of ASME Turbo Expo 2014, June 16-20, 2014, D{\"u}sseldorf, Germany}, author = {Reichel, T. G. and Terhaar, S. and Paschereit, C. O.} } @Article { OberleithnerTRP2013, title = {Why Non-Uniform Density Suppress the Precessing Vortex Core}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2013}, month = {9}, day = {23}, volume = {135}, number = {12}, pages = {121506 (9 Pages)}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4025130}, author = {Oberleithner, K. and Terhaar, S. and Rukes, L. and Paschereit, C. O.} } @Article { Krueger2013, title = {Large Eddy Simulations of Hydrogen Oxidation at Ultra-Wet Conditions in a Model Gas Turbine Combustor Applying Detailed Chemistry}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2013}, month = {1}, day = {3}, volume = {135}, number = {2}, pages = {021501 (10 pages)}, url = {http://link.aip.org/link/?GTP/135/021501/1}, publisher = {ASME}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4007718}, author = {Kr{\"u}ger, O. and Terhaar, S. and Paschereit, C. O. and Duwig, C.} } @Article { Goeke2012b, title = {Influence of steam dilution on the combustion of natural gas and hydrogen in premixed and rich-quench-lean combustors}, journal = {Fuel Processing Technology}, year = {2013}, number = {107}, pages = {14-22}, url = {http://www.sciencedirect.com/science/article/pii/S0378382012002408}, web_url = {Goeke_FuProc2012.pdf}, ISSN = {0378-3820}, DOI = {10.1016/j.fuproc.2012.06.019}, author = {G{\"o}ke, S. and F{\"u}ri, M. and Bourque, G. and Bobusch, B. and G{\"o}ckeler, K. and Kr{\"u}ger, O. and Schimek, S. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { PaschereitTOo2013, title = {Application of Linear Hydrodynamic Stability Analysis to Reacting Swirling Combustor Flows}, year = {2013}, booktitle = {Proceedings of 4th International Conference on Jets, Wakes and Separated Flows (ICJWSF), Sep 17-21, 2013, Nagoya, Aichi, Japan}, ISBN = {978-4-88898-234-4 (CD)}, author = {Paschereit, C. O. and Terhaar, S. and Oberleithner, K. and \'{C}osi\'{c}, B.} } @Inproceedings { Nayeri2013a, title = {Experimental challenges of the prediction of the slipstream effect of high speed trains in a wind tunnel with a stationary floor}, year = {2013}, volume = {44}, pages = {9-27}, publisher = {Interdisziplin{\"a}rer Forschungsverbund (IFV) Bahntechnik e.V., Salzufer 17-19, 10587 Berlin, Germany}, series = {Bahntechnik aktuell, Schriftenreihe des Interdisziplin{\"a}ren Forschungsverbundes Bahntechnik e.V.}, booktitle = {2nd international symposium on Rail Aerodynamics, Aerodynamics of Trains and Infrastructure, Berlin, Germany}, ISBN = {978-3-940727-37-4}, ISSN = {1867-240X}, author = {Nayeri, C. N. and Gencaslan, U. and Tietze, A. and Strangfeld, C. and Sieber, M. and Wieser, D. and Weise, M. and Paschereit, C. O.} } @Inproceedings { Reichel2013d, title = {Flow Field Manipulation by Axial Air Injection to Achieve Flashback Resistance and its Impact on Mixing Quality}, year = {2013}, number = {AIAA paper no. 2013-2603}, url = {http://arc.aiaa.org/doi/pdfplus/10.2514/6.2013-2603}, booktitle = {51st AIAA Aerospace Science Meeting, Grapevine, Texas, USA, Jan. 07-10}, DOI = {10.2514/6.2013-2603}, author = {Reichel, T. G. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Terhaar2013, title = {Impact of Shear Flow Instabilities on the Magnitude and Saturation of the Flame Response}, year = {2013}, number = {ASME paper GT2013-95729}, pages = {V01BT04A056 (13 pages)}, booktitle = {Proc. ASME Turbo Expo 2013, June 3-7, San Antonio, Texas, USA}, ISBN = {978-0-7918-5511-9}, DOI = {10.1115/GT2013-95729}, author = {Terhaar, S. and \'{C}osi\'{c}, B. and Oberleithner, K. and Paschereit, C. O.} } @Inproceedings { Cosic2012d, title = {Influence of pressure and steam dilution on NOx and CO emissions in a premixed natural gas flame}, year = {2013}, number = {ASME paper GT2013-94782}, pages = {V01AT04A056 (11 pages)}, booktitle = {Proc. ASME Turbo Expo 2013, June 3-7, San Antonio, Texas, USA}, ISBN = {978-0-7918-5510-2}, DOI = {10.1115/GT2013-94782}, author = {G{\"o}ke, S. and Schimek, S. and Terhaar, S. and Reichel, T. G. and G{\"o}ckeler, K. and Kr{\"u}ger, O. and Fleck, J. and Griebel, P. and Paschereit, C. O.} } @Inproceedings { Kruger2013a, title = {Large Eddy Simulations of Methane Oxidation at Ultra-Wet Conditions in a Model Gas Turbine Combustor Applying Detailed Chemistry}, year = {2013}, pages = {1--6}, publisher = {Japan Society of Mechanical Engineers}, booktitle = {Proceedings of 4th International Conference on Jets, Wakes and Separated Flows (ICJWSF), Sep 17-21, 2013, Nagoya, Aichi, Japan}, ISBN = {978-4-88898-234-4 (CD)}, author = {Kr{\"u}ger, O. and Duwig, C. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Kruger2013b, title = {Numerical Investigations and Modal Analysis of the Coherent Structures in a Generic Swirl Burner}, year = {2013}, number = {AIAA paper 2013-2953}, pages = {1--16}, url = {http://arc.aiaa.org/doi/abs/10.2514/6.2013-2953}, publisher = {American Institute of Aeronautics and Astronautics}, booktitle = {21th AIAA Computational Fluid Dynamics Conference, June 24-27, 2013, San Diego, California, USA}, DOI = {10.2514/6.2013-2953}, author = {Kr{\"u}ger, O. and Duwig, C. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Goeckeler2013a, title = {Residence Time Distribution in a Swirling Flow at Non-Reacting, Reacting, and Steam-Diluted Conditions}, year = {2013}, volume = {Volume 1B: Combustion, Fuels and Emissions}, number = {ASME paper GT2013-95594}, pages = {V01BT04A047 (12 pages)}, booktitle = {Proc. ASME Turbo Expo 2013, June 3-7, San Antonio, Texas, USA}, ISBN = {978-0-7918-5511-9}, DOI = {10.1115/GT2013-95594}, author = {G{\"o}ckeler, K. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { TerhaarBP2013, title = {Untersuchung einer drallstabilisierten Freistrahlflamme mit azimutaler Anregung}, year = {2013}, pages = {37.1-37.8}, editor = {K{\"a}hler, C. and Hain, R. and Cierpka, C. and Ruck, B. and Leder, A. and Dopheide, D.}, booktitle = {Proceedings der 21. GALA-Fachtagung ''Lasermethoden in der Str{\"o}mungsmesstechnik'', 3.-5. September 2013, Universit{\"a}t der Bundeswehr, M{\"u}nchen, Germany}, ISBN = {978-3-9805613-9-6 (print)}, ISSN = {2194-2447}, author = {Terhaar, S. and Beuth, J. and Paschereit, C. O.} } @Inproceedings { Terhaar2013a, title = {Vortex Breakdown and Global Modes in Swirling Combustor Flows with Axial Air Injection}, year = {2013}, pages = {1--16}, url = {http://arc.aiaa.org/doi/pdfplus/10.2514/6.2013-2602}, booktitle = {Proceedings of 43st AIAA Fluid Dynamics Conference and Exhibit, June 24-27 2013, San Diego, CA, USA}, DOI = {10.2514/6.2013-2602}, author = {Terhaar, S. and Reichel, T. G. and Schr{\"o}dinger, C. and Rukes, L. and Oberleithner, K. and Paschereit, C. O.} } @Inproceedings { Oberleithner2013, title = {Why Non-Uniform Density Suppress the Precessing Vortex Core}, year = {2013}, number = {ASME paper GT2013-95509}, pages = {V01BT04A041 (12 pages)}, booktitle = {Proc. ASME Turbo Expo 2013, June 3-7, San Antonio, Texas, USA}, ISBN = {978-0-7918-5511-9}, DOI = {10.1115/GT2013-95509}, author = {Oberleithner, K. and Terhaar, S. and Rukes, L. and Paschereit, C. O.} } @Inproceedings { Nayeri2013c, title = {Wind tunnel experiments on the control of the lee side vortex of high-speed trains}, year = {2013}, pages = {1--6}, web_url = {nayeri_ICJWSF_2013.pdf}, publisher = {Japan Society of Mechanical Engineers}, booktitle = {Proceedings of 4th International Conference on Jets, Wakes and Separated Flows (ICJWSF), Sep 17-21, 2013, Nagoya, Aichi, Japan}, ISBN = {978-4-88898-234-4 (CD)}, author = {Nayeri, C. N. and Neumann, U. and Tschepe, J. and Strangfeld, C. and Wieser, D. and Paschereit, C. O.} } @Article { TerhaarBP2012_2, title = {Effects of Outlet Boundary Conditions on the Reacting Flow Field in a Swirl-Stabilized Burner at Dry and Humid Conditions}, journal = {Journal of Engineering for Gas Turbines and Power}, year = {2012}, month = {9}, day = {20}, volume = {134}, number = {11}, pages = {111501}, ISSN = {0742-4795 (online), 1528-8919 (print)}, DOI = {10.1115/1.4007165}, author = {Terhaar, S. and Bobusch, B. and Paschereit, C. O.} } @Inproceedings { Schimek2012c, title = {Amplitude-dependent flow field and flame response to axial and tangential velocity fluctuations}, year = {2012}, number = {ASME paper GT2012-69785}, pages = {1321-1333 (13 pages)}, booktitle = {Proc. ASME Turbo Expo 2012, June 11-15, Bella Center, Copenhagen, Denmark}, ISBN = {978-0-7918-4468-7}, DOI = {10.1115/GT2012-69785}, author = {Schimek, S. and \'{C}osi\'{c}, B. and Moeck, J. P. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { TerhaarBP2012, title = {Effects of Outlet Boundary Conditions on the Reacting Flow Field in a Swirl-Stabilized Burner at Dry and Humid Conditions}, year = {2012}, pages = {1295-1306 (12 pages)}, booktitle = {Proc. ASME Turbo Expo 2012, June 11-15, Bella Center, Copenhagen, Denmark , ASME paper GT2012-69753}, ISBN = {978-0-7918-4468-7}, DOI = {10.1115/GT2012-69753}, author = {Terhaar, S. and Bobusch, B. and Paschereit, C. O.} } @Inproceedings { TerhaarP2012, title = {High-Speed PIV Investigation of Coherent Structures in a Swirl-Stabilized Combustor Operating at Dry and Steam-Diluted Conditions}, year = {2012}, url = {http://ltces.dem.ist.utl.pt/lxlaser/lxlaser2012/upload/212_paper_bysdxt.pdf}, booktitle = {16th Int Symp on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 09-12 July, 2012}, author = {Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Goeke2012a, title = {Influence of Steam Dilution on the Combustion of Natural Gas and Hydrogen in Premixed and Rich-Quench-Lean Combustors}, year = {2012}, booktitle = {The Eleventh International Conference on Combustion and Energy Utilization (11th ICCEU)}, author = {G{\"o}ke, S. and F{\"u}ri, M. and Bourque, G. and G{\"o}ckeler, K. and Kr{\"u}ger, O. and Bobusch, B. and Schimek, S. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Kruger2012, title = {Large Eddy Simulations of Hydrogen Oxidation at Ultra-wet Conditions in a Model Gas Turbine Combustor Applying Detailed Chemistry}, year = {2012}, number = {ASME paper GT2012-69446}, pages = {1081-1094 (14 pages)}, booktitle = {Proc. ASME Turbo Expo 2012, June 11-15, Bella Center, Copenhagen, Denmark}, ISBN = {978-0-7918-4468-7}, DOI = {10.1115/GT2012-69446}, author = {Kr{\"u}ger, O. and Duwig, C. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Goeke2012c, title = {Ultra-wet Combustion For High Efficiency, Low Emission Gas Turbines}, year = {2012}, pages = {Paper ID Number: 17}, web_url = {Goeke2012c.pdf}, booktitle = {European Turbine Network ETN: The Future of Gas Turbine Technology, 6th IGTC, Brussels, Belgium, Oct. 17-18}, author = {G{\"o}ke, S. and Albin, E. and G{\"o}ckeler, K. and Kr{\"u}ger, O. and Schimek, S. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Krueger2012, title = {Ultra-Wet Operation of a Hydrogen Fueled GT Combustor: Large Eddy Simulation Employing Detailed Chemistry}, year = {2012}, url = {http://www.iccfd.org/iccfd7/assets/pdf/papers/ICCFD7-3403_paper.pdf}, booktitle = {Seventh International Conference on Computational Fluid Dynamics (ICCFD7), Big Island, Hawaii, July 9-13}, author = {Kr{\"u}ger, O. and Duwig, C. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Strangfeld2011b, title = {3D Visualisation of Measured Coherent Structures in a Swirling Water Flow}, year = {2011}, pages = {36.1--36.9}, booktitle = {Proceedings der 19. GALA-Fachtagung ''Lasermethoden in der Str{\"o}mungsmesstechnik'', 2011, Ilmenau, Germany}, ISBN = {978-3-9805613-7-2 (print)}, author = {Strangfeld, C. and G{\"o}ckeler, K. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Goeke2011, title = {Combustion Of Natural Gas, Hydrogen And Bio-fuels At Ultra-wet Conditions}, year = {2011}, number = {ASME paper GT2011-45696}, booktitle = {Proc. ASME Turbo Expo 2011: Advancing Clean and Efficient Turbine Technology (GT2011), June 6-10, Vancouver, BC, Canada}, author = {G{\"o}ke, S. and Terhaar, S. and Schimek, S. and G{\"o}ckeler, K. and Paschereit, C. O.} } @Inproceedings { Kruger2011c, title = {Identification of Coherent Structures in a Turbulent Generic Swirl Burner using Large Eddy Simulations}, year = {2011}, number = {AIAA paper 2011-3549}, pages = {1--14}, abstract = {The isothermal flow dynamics of a generic swirl burner are studied employing large eddy simulation (LES). A sensitivity analysis was conducted, considering different mesh sizes and subgrid-scale models and the results were compared to experimental data. It was found that the overall influence of the computational grid and the subgrid-scale model was neglectable and the simulations were in line with the experiments. A dominant frequency was found in the turbulent kinetic energy spectrum representing a coherent structure. Moreover, by applying the proper orthogonal decomposition (POD) this structure could be identified as a convective helical instability. This helical instability and can be represented by a pair of modes, and is assumed to be triggered by a precessing vortex core (PVC).}, booktitle = {20th AIAA Computational Fluid Dynamics Conference, June 27-30, 2011, Honolulu, Hawaii, USA}, author = {Kr{\"u}ger, O. and Duwig, C. and G{\"o}ckeler, K. and Terhaar, S. and Strangfeld, C. and Paschereit, C. O. and Fuchs, L.} } @Inproceedings { Goeke2011b, title = {Investigation of NOx and CO Formation in a Premixed Swirl-Stabilized Flame at Ultra Wet Conditions}, year = {2011}, number = {AIAA paper no. 2011-5535}, booktitle = {47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, San Diego, California, Jul 31 -- Aug 3}, author = {G{\"o}ke, S. and Schimek, S. and Fateev, A. and Clausen, S. and Kuhn, P. and Terhaar, S. and Paschereit, C. O.} } @Inproceedings { Terhaar2011, title = {Non-Reacting and Reacting Flow in a Swirl-Stabilized Burner for Ultra-Wet Combustion}, year = {2011}, number = {AIAA paper no. 2011-3584}, pages = {1--14}, abstract = {The flow field of a swirl-stabilized burner for ultra-wet combustion is experimentally investigated by assessing the isothermal and the reacting flow. The ultra-wet combustion technique promises high cycle efficiency and low NOx emissions. Investigations of the non- reacting flow field are carried out in a water tunnel facility and the reacting flow is assessed in an atmospheric combustion test rig. Experiments were conducted at a theoretical swirl number of 0.7 and Reynolds numbers in the range of 22,000 to 32,000. Particle Image Velocimetry and OH-Chemiluminescence are employed to measure the flow velocities as well as the spatial distribution of heat release. The effect of steam addition up to levels of 30\% of the air mass flow is investigated for natural gas fuel and mixtures of natural gas and hydrogen. The results show a strong impact of steam addition on the flow field and the position of the reaction zone. In particular, three different flow patterns were found. Dry flames and hydrogen flames show a broad inner recirculation zone with very low local turbulent kinetic energy. At high rates of steam dilution, the flow fields show good agreement to the non-reacting flow field in water as well as in isothermal air. At intermediate to high steam dilution rates the flame shows a trumpet like shape. Several sudden changes of the flow field and flame shapes could be observed for various operating conditions.}, booktitle = {Proc. 41st AIAA Fluid Dynamics Conference and Exhibit, 27-30 June, Honolulu, Hawaii}, ISBN = {978-1-61839167-4 (DVD)}, author = {Terhaar, S. and G{\"o}ckeler, K. and Schimek, S. and G{\"o}ke, S. and Paschereit, C. O.} } @Inproceedings { Strangfeld2011a, title = {Parametric Investigations of the Leading Edge Vortex on a Delta Wing}, year = {2011}, number = {AIAA-2011-3895}, pages = {1--12}, booktitle = {20th AIAA Computational Fluid Dynamics Conference, June 27-30, 2011, Honolulu, Hawaii, USA}, author = {Strangfeld, C. and Nayeri, C. N. and Taubert, L. and Paschereit, C. O.} } @Inproceedings { Goeckeler2011, title = {Residence Time Distribution in a Swirl-Stabilized Combustor at Cold Conditions}, year = {2011}, number = {AIAA-2011-3585}, pages = {13}, abstract = {Reactor network models are widely used in studies of combustion kinetics. The mean residence time in the reactors is a crucial input for these models, however few attempts have been conceived so far to determine it accurately. In this study, the temporal and spatial distribution of a fluorescent tracer, injected as a short pulse, was measured using Highspeed planar laser-induced fluorescence (HS-PLIF), and Particle Image Velocimetry (PIV) was utilized for measuring the flow field. In a pulse experiment the tracer response in the combustor exit stream almost readily yields the residence time density function, which directly gives the mean residence time in the combustor. For a volume element within the combustor, the respective tracer response yields the time delay from the injection until the elements exit, but not its residence time, due to dispersion of the tracer input. The density function describes the deviation from the ideal transport in a plug flow and a perfectly mixed flow by considering two characteristic times: (1) a convective time delay \(\tau\)c, representing the time until the first detection of the tracer, and (2) a dispersive time delay \(\tau\)d, which characterizes the degree of dispersion upstream,and mixing within the respective volume element. A plug flow is solely described by \(\tau\)c, whereas a perfectly mixed flow is characterized only by \(\tau\)d. Time density functions were obtained at the injection holes, the combustion chamber inlet and outlet, as well as in an axicentric cross-section of the combustion chamber. The shape of density functions in the combustion chamber varies between that of an approx- imate plug flow and perfectly mixed flow, but mostly is represented by a superposition of the two. The distribution of \(\tau\)c indicates the path of the tracer through the combus- tor. By means of the \(\tau\)d distribution, zones of similar mixing characteristics are identified. The external recirculation zone (ERZ) is among these; however, only part of the internal recirculation zone (IRZ), that is less effected by entrainment from the jet, exhibits these similar mixing characteristics. Based on the experimental findings, a semi-empirical re- actor network model was developed applying an extended tanks-in-series approach. The model agrees very well with the measured time density functions. The transfer functions of the recirculation zones are used to determine the actual mean residence time in these zones. The mean residence time in the IRZ yields 21\% of the total combustor residence time and 25\% in the ERZ.}, booktitle = {Proc. 41st AIAA Fluid Dynamics Conference and Exhibit, 27-30 June, Honolulu, Hawaii}, ISBN = {978-1-61839167-4 (DVD)}, author = {G{\"o}ckeler, K. and Terhaar, S. and Lacarelle, A. and Paschereit, C. O.} } @Article { TerhaarVAS2010, title = {Experimental study on the unsteady laminar heat transfer downstream of a backwards facing step}, journal = {International Communications in Heat and Mass Transfer}, year = {2010}, volume = {37}, number = {5}, pages = {457-462}, ISSN = {07351933}, DOI = {10.1016/j.icheatmasstransfer.2010.01.009}, author = {Terhaar, S. and Velazquez, A. and Arias, J. R. and Sanchez-Sanz, M.} } @Inproceedings { Lacarelle2009, title = {Dynamic Mixing Model of a Premixed Combustor and Validation with Flame Transfer Function Measurements}, year = {2009}, number = {AIAA paper no. AIAA-2009-986}, booktitle = {47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, Jan. 5-8, 2009, Orlando, Florida, USA}, ISBN = {1-56347-969-9 (DVD)}, author = {Lacarelle, A. and Moeck, J. P. and Tenham, A. and Paschereit, C. O.} } @Inproceedings { Hoefener2009, title = {Wind tunnel experiments of a high speed train exposed to cross wind on ground and bridge configurations}, year = {2009}, booktitle = {EUROMECH COLLOQUIUM 509 ''Vehicle Aerodynamics External Aerodynamics of Railway Vehicles, Trucks, Buses and Cars'', 24-26 M{\"a}rz 2009, Berlin, Germany}, author = {Hoefener, L. and Romann, D. and Nayeri, C. N. and Tielkes, Th. and Paschereit, C. O.} } @Inproceedings { Guyot2008b, title = {Active control of combustion instability using a fluidic actuator}, year = {2008}, number = {paper no. AIAA 2008-1058}, booktitle = {Proc. 46th AIAA Aerospace Sciences Meeting and Exhibit, 7-10 January 2008, Reno, Nevada, USA}, ISBN = {978-1-56347-937-0}, author = {Guyot, D. and Taticchi Mandolini Borgia, P. and Paschereit, C. O. and Raghu, S.} } @Inproceedings { Bellucci2002, title = {Numerical and experimental study of acoustic damping generated by acoustic screens with bias flow}, year = {2002}, booktitle = {ASME Turbo Expo, June 3-6, 2002, Amsterdam, Netherlands.}, author = {Bellucci, V. and Paschereit, C. O. and Tabacco, D. and Flohr, P.} }