Predictions of unsteady hawt aerodynamics by lifting line theory

A numerical engineering method for the prediction of unsteady wind turbine aerodynamics is presented. The formulation is based on lifting line theory and a semiempirical dynamic stall model of Leishman and Beddoes. The unsteady aerodynamic response of the blade aerodynamics to the sharp blade-pitch changes or unsteady wind conditions is achieved by superposition of the above methods. Comparisons between computed and measured blade loading show the adequacy of the proposed method to predict instantaneous loading of wind turbines during coaxial transient flow situations.