Accuracy of Dynamic Stall Response for Wind Turbine Airfoils Based On Semi-Empirical and Numerical Methods

Abstract

The aim of the present study is to investigate the accuracy of two different dynamic stall approaches for wind-turbine airfoils. The first approach is the semi-empirical Leishman-Beddoes model (L-B), and the second is the computational fluid dynamic (CFD) results. National Renewable-Energy Laboratory (NREL) S series airfoils are used, and the simulations are performed in Re=106. For both approaches, aerodynamic coefficients are represented and compared to experimental data. Validation data refer to Ohio State University (OSU) experiments, which are for pitch oscillation. Results show that the accuracy of the L-B and CFD methods is dependent on mean angle of attack, reduced frequency and the phase of motion. The semi-empirical model has appropriate accuracy as well as low computational cost while the CFD unsteady simulation could be properly used to predict the drag coefficient.

Keywords

• Dynamic stall; Wind turbine airfoils; Semi-Empirical model; Numerical method.