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Qblade is an open source wind turbine calculation software, distributed under the GPL. The motivation for this was to create a one solution software for the design and aerodynamical computation of wind turbine blades

Download and Project-Homepage https://sourceforge.net/projects/qblade/

Main Features

The software is seamlessly integrated into XFOIL, an airfoil design and analysis tool. This integration allows the user to rapidly design custom airfoils and com pute their polars, extrapolate the polar data to a range of 360°, and directly integrate them into a wind turbine rotor-simulation. This skips the step of exporting and importing foil and geometry data between different codes, and the troubles associated with that. At the same time the integration of QBlade into XFOIL’s sophisticated GUI (XFLR5) makes this software accessible to many more interested people than the usual command line interface software tools. The software is especially adequate for teaching, as it provides a ’hands on’ feeling for HAWT rotor design and shows all the fundamental relationships and concepts between twist, chord, foils, turbine control and type and the power  and load curves in an easy and intuitive way. QBlade also includes post processing of conducted rotor simulations and gives deep insight into all relevant blade and ro tor variables for verification, to compare different rotor configurations, or even to study the numerical algorithm (Blade Element Momentum Theory) and the dependency’s among the aerodynamic variables themselves. In addition to that ,the resulting software is a very flexible and user-friendly platform for wind turbine blade design that can also act as a modular system for future implementations that can exploit the possibilities that a combination of manual and parametric airfoil design and analysis coupled with a blade design and simulation tool offers.


  • Extrapolation of XFOIL generated or imported polar data to 360° AoA
  • Blade design and optimization, including 3D visualization, using XFOIL generated or imported profiles
  • Turbine definition (rotor blade, turbine control, generator type, losses...)
  • Computation of rotor performance over lambda (tip speed ratio) range
  • Computation of turbine performance over wind speed range
  • Annual yield computation with WEIBULL distribution
  • Manual selection of BEM correction algorithms
  • Manual selection of all simulation parameters
  • Data browsing and visualization as post processing
  • Export functionality for all created simulation data
  • Blade geometry export functionality
  • Storing of projects, rotors, turbines and simulations in a runtime database

Further Details

QBlade is based on a Blade Element Momentum Theory (BEM) algorithm which is integrated to the main XFLR5 code in the form of an additional module.The Blade Design Module of the code includes several sub-modules, which assist the blade design process. The 360° Polar sub-module provides the means for the efficient and accurate blending of the C_l and C_d (lift and drag coefficients) curves computed with XFOIL or wind tunnel data (imported) with a generic 360° polar, which is based on the flat plate theory. The blade design sub-module allows the fast and flexible blade design via a user friendly interface and several shape optimization algorithms. The blade can be optimized in terms of chord and twist for various wind turbine configurations and operational regimes. The rotor Blade Element Momentum (BEM) sub-module computes all the necessary aerodynamic and load parameters for various rotor tip-speed ratios (rotor simulation) or wind speeds (turbine simulation). The standard Prandtl tip and root loss corrections are implemented in the code as well as additional correction algorithms. One additional correction model is the 3D correction for the blade cross flow effects. The Turbine BEM sub-module provides results for the complete performance of an actual wind turbine. The user can define the turbine type and its operational parameters and then compute the exact turbine behavior and performance. With the introduction of a wind speed Weibull distribution, the code is able to calculate the wind turbines annual energy yield thus completing the whole simulation. All simulation parameters of the BEM, like residual, number of iterations, element size, polar interpolation or resolution of the simulation can be defined by the user. In addition to the standard BEM functions the software serves as a tool to compare different blade designs and their performance and deeply investigate the distribution of all relevant variables along the rotor, such as the critical roughness size for each span-wise station of the blade. This computation combined with the inherent ability of XFOIL to compute the boundary layer thickness along the airfoil chord informs the wind turbine blade designer about the required manufacturing specifications of each blade design. Another valuable advantage that comes out from this successful combination of the BEM code with XFLR5 is the seamless integration of airfoil design. After the initial blade design, the user is able to see possible defects or limitations in the current blades performance. The software allows the easy replacement of one or more airfoils with new ones or even the direct as well as inverse design of completely custom airfoils. These new airfoils can be directly included and computed in the BEM code. Even the possibility of airfoil dynamic coordinate mixing is available, giving the designer endless experimentation freedom.

Auxiliary Functions / Extras

Help Functions