An insight into the separate flow and stall delay for HAWT

The flow characteristics and the stall delay phenomenon of wind turbine rotor due to blade rotation in the steady state non-yawed conditions are investigated. An incompressible Reynolds-averaged Navier–Stokes solver is applied to carry out all the cases at different wind speeds from 5 m/s to 10 m/s with an interval of 1 m/s. CFD results turn out to agree well with experimental ones at incoming wind speeds below 10 m/s, though at 10 m/s some deviations exist due to the relative large flow separation and 3D spanwise flow over the suction surface of the blade. In the meanwhile, a lifting surface code with and without Du–Selig stall delay model is used to predict the power. A MATLAB code is developed to extract aerodynamic force coefficients from 3D CFD computations which are compared with the 2D airfoil wind tunnel experiment to demonstrate the stall delay and augmented lift phenomenon particularly at inboard span locations of the blade. The computational results are compared with the corrected value by the Du–Selig model and a lifting surface method derived data based on the measurements of the Unsteady Aerodynamic Experiment at the NASA Ames wind tunnel.

[1]  N. Sørensen,et al.  Rotor performance predictions using a Navier-Stokes method , 1998 .

[2]  J. Michelsen,et al.  Aerodynamic predictions for the Unsteady Aerodynamics Experiment Phase-II rotor at the National Renewable Energy Laboratory , 2000 .

[3]  Florian R. Menter,et al.  Transition Modelling for General Purpose CFD Codes , 2006 .

[4]  Lakshmi N. Sankar,et al.  Effects of transition, turbulence and yaw on the performance of horizontal axis wind turbines , 2000 .

[5]  James L. Tangler,et al.  Insight into Wind Turbine Stall and Post-stall Aerodynamics , 2004 .

[6]  Maureen Hand,et al.  Unsteady Aerodynamics Experiment Phase VI: Wind Tunnel Test Con gurations and Available Data Campaigns , 2001 .

[7]  Scott Schreck,et al.  Detached‐eddy simulation of flow around the NREL Phase VI blade , 2002 .

[8]  J. C. Narramore,et al.  Navier-Stokes calculations of inboard stall delay due to rotation , 1992 .

[9]  L. A. Viterna,et al.  Fixed pitch rotor performance of large horizontal axis wind turbines , 1982 .

[10]  Earl P. N. Duque,et al.  Navier-Stokes simulations of the NREL Combined Experiment Phase II rotor , 1999 .

[11]  Niels N. Sørensen,et al.  Extraction of Lift, Drag and Angle of Attack from Computed 3-D Viscous Flow around a rotating Blade , 1997 .

[12]  Jeppe Johansen,et al.  Aerofoil characteristics from 3D CFD rotor computations , 2004 .

[13]  A. Le Pape,et al.  3D Navier–Stokes computations of a stall‐regulated wind turbine , 2004 .

[14]  F. Menter,et al.  A Correlation-Based Transition Model Using Local Variables—Part I: Model Formulation , 2006 .

[15]  Vladimir Cardos,et al.  Rotational Effects on the Boundary-Layer Flow in Wind Turbines , 2004 .

[16]  M. Selig,et al.  A 3-D stall-delay model for horizontal axis wind turbine performance prediction , 1998 .

[17]  Lakshmi N. Sankar,et al.  Computational study of horizontal axis wind turbines , 1999 .

[18]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[19]  P. K. Chaviaropoulos,et al.  Investigating Three-Dimensional and Rotational Effects on Wind Turbine Blades by Means of a Quasi-3D Navier-Stokes Solver , 2000 .