Unsteady Free-Wake Vortex Particle Model for HAWT

In the design of horizontal axis wind turbines (HAWT) one problem is to determine the aeroelastic behaviour of the rotor blades for the various wind inflow conditions. A step in this process is to predict with accuracy the aerodynamic loads on the blades. The Vortex Lattice Method (VLM) provides a transparent investigation concerning the role of various physical parameters which influence the aerodynamic problem. In this paper we present a method for the calculation of the non‐uniform induced downwash of a HAWT rotor using the vortex ring model for the lifting surface coupled with an unsteady free‐wake vortex particle model. Comparative studies between results obtained with different models of wake for a generic HAWT are presented.