Numerical Predictions of Wind Turbine Power and Aerodynamic Loads for the NREL Phase II Combined Experiment Rotor

摘要

A blade element momentum (BEM), vortex lattice (VL) and a Reynolds- averaged thin-layer Navier-Stokes method (RaNS) were evaluated for their ability to predict the aerodynamic performance of the Combined Experiment Phase II Horizontal Axis Wind Turbine. To evaluate blade stall modeling, the BEM and VL methods utilized the Du-Selig stall delay model along with experimental and computationally derived airfoil characteristics. To validate the methods, experimental data from the IEA Annex XIV database were used. Additional data reduction was applied to sort the experimental data into steady wind speed bins with known error and to make it suitable for validation of numerical methods. All three methods produce good power and sectional normal force predictions at pre-stall wind conditions. The RaNS method fails to capture the correct aerodynamic performance once the blade begins to stall. The VL and BEM methods show better capability in predicting post stall behavior, however to obtain more accurate power and load predictions they need improved stall delay models and adequate airfoil properties. Predicting the correct inboard stall delay is still a challenge to these methods.