Dynamic stall on rotating airfoils: A look at the N-sequence data from the NREL Phase VI experiment.

摘要

This paper presents an investigation on the combined effect of dynamic stall and rotational augmentation on wind turbine blades, using the N-sequence data of the NREL Phase VI experiment. Unsteady DES CFD computations of the Phase VI rotor in axial operation and continuous pitching conditions for select cases have been carried out. A set of C_L — α curves for different blade sections operating at various values of the frequency, the mean, and the amplitude of the angle of attack (AOA) extracted from the CFD as well as the experimental data and are presented. Qualitative differences between dynamic stall occurrence on rotating and stationary airfoils are highlighted, procedures employed to extract the mean AOA from the available experimental data are discussed, and comments are made on the application of dynamic stall models in conjunction with the rotational augmentation models on the rotating wind turbine blades.