Calculation Of The Three-Dimensional Unsteady Aerodynamic Characteristics Of Horizontal Axis Wind Turbines

A three-dimensional unsteady aerodynamic model for horizontal axis wind turbine performance prediction is presented. The flowfield around the turbine is calculated using the prescribed wake model. In particular, a vortex core model and a vorticity dissipation model are introduced to cope with the divergence generally existing in vortex wake methods. The Leishman-Beddoes dynamic stall model is modified and then used to provide the unsteady characteristics of the blade due to the yaw wind. A modified three-dimensional stall delay model is coupled with the method to calculate the unsteady aerodynamic response of the blade due to the rotational effect.The method presented in this paper is applied to calculate gross rotor performance and unsteady aerodynamic airloads in two-dimensional and three-dimensional conditions for different flow environments, which are compared with experiment results. The calculated results demonstrate that the wind turbine unsteady aerodynamic performance prediction is improved using the modified approach presented in the paper. For completeness, the scheme and the calculated results in this paper are discussed and analyzed in some detail.