Application of a free vortex wake model to a horizontal axis wind turbine

1992 ◽  
Vol 39 (1-3) ◽  
pp. 129-138 ◽  
Author(s):  
F.J. Simoes ◽  
J.M.R. Graham
Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3900 ◽  
Author(s):  
Jing Dong ◽  
Axelle Viré ◽  
Carlos Simao Ferreira ◽  
Zhangrui Li ◽  
Gerard van Bussel

A modified free-wake vortex ring model is proposed to compute the dynamics of a floating horizontal-axis wind turbine, which is divided into two parts. The near wake model uses a blade bound vortex model and trailed vortex model, which is developed based on vortex filament method with straight lifting lines assumption. By contrast, the far wake model is based on the vortex ring method. The proposed model is a good compromise between accuracy and computational cost, for example when compared with more complex vortex methods. The present model is used to assess the influence of floating platform motions on the performance of a horizontal-axis wind turbine rotor. The results are validated on the 5 MW NREL rotor and compared with other aerodynamic models for the same rotor subjected to different platform motions. The results show that the proposed method is reliable. In addition, the proposed method is less time consuming and has similar accuracy when comparing with more advanced vortex based methods.


Author(s):  
Xiancheng Song ◽  
Jiang Chen ◽  
Gang Du ◽  
Lucheng Ji

The aerodynamic analysis and optimization of wind turbine based on a full free vortex wake model is presented. Instead of a simplification of the vortex wake structure, this model predict an adequate free-wake extension which can accurately take into account the profound influence of vortex sheet downstream on the aerodynamic performance of wind turbine. The problem that the model suffers from high computational costs is solved by combining the Fast Multipole Methods (FMM) for an efficient evaluation of the Biot–Savart law with the parallel processing. The model is applied to the aerodynamic analysis of wind turbine and a stable convergent numerical solution is achieved using the pseudo-implicit technique (steady) and predictor-corrector PC2B scheme (unsteady). The optimization based on this analysis is also efficiently carried out using a Fourier series representation of the bound circulation as optimization variables, using a given thrust coefficient as a constraint. The chord and twist distributions that completely define the geometry are produced from the obtained optimal bound circulation distribution. The optimization is capable of quickly finding an optimum design using a few optimization variables. The validations of presented methods are performed through comparisons with the National Renewable Energy Laboratory (NREL) wind turbine experiment.


2013 ◽  
Vol 448-453 ◽  
pp. 1716-1720
Author(s):  
Rui Yang ◽  
Jiu Xin Wang ◽  
Sheng Long Zhang

A computational method based on nonlinear wake model was established for horizontal axis wind turbines aerodynamic performance prediction. This method makes use of finite difference method to solve the integral differential equation of the model, the induced velocity of wake vortex can be calculated from equations and compared with the induced velocity of wake vortex in linear model. The comparison between the calculated results of wind turbine under axis flow condition, including tip vortex geometry and aerodynamic performance, and available experimental data shows that this method is suitable for wind turbine aerodynamic performance analysis. Finally, a series of numerical calculations were made to investigate the change of wake geometry and aerodynamic performance of the wind turbine when yawing and pitch angle increasing, which provide foundations for aerodynamic optimization design of horizontal axis wind turbines.


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