Boundary element analysis of unsteady aerodynamics of windmill rotors in the presence of yaw

Abstract In this paper a method for the evaluation of pressure and velocity fields for a horizontal-axis wind turbine in the presence of yaw is presented. The flow is assumed to be potential and incompressible. The formulation used is general and is applicable to unsteady incompressible potential flows around wind turbines, as well as aircraft and ship propellers. In order to assess the importance of the wake geometry a free-wake analysis is included in this paper. Comparisons with experimental results are also included.