Analysis of wind turbine blades aeroelastic performance under yaw conditions

The aeroelastic modeling of Tjæreborg wind turbine blades was performed based on the unsteady Reynolds Averaged Navier-Stokes equations (URANS) combined with Finite Element Method (FEM) in a loosely coupled manner. This method was verified by comparing numerical and experiment results at four axial inflow wind speeds. Furthermore, the aeroelastic performance of Tjæreborg wind turbine under yaw angle of 10°, 30° and 60°were computed and analyzed. The results showed that the average power and thrust of the wind turbine decreased with increasing yaw angle, along with the increasing oscillation amplitude under large yaw angle. The aerodynamic load showed periodic change within one revolution of rotor, resulting in the blade deflection and the strain present considerably asymmetric distributions. The maximum deflection and strain occurred at azimuth angle of about90° and their minimum values occurred at azimuth angle of about 270°. Besides, both the maximum deflection and strain under yaw conditions became larger than those in axial inflow condition do. For Tjæreborg wind turbine, the coupled solver gave a higher average power and thrust than the CFD solver alone. The aerodynamic performances showed more asymmetrical characters under the combined effect of yaw and fluid structure interaction (FSI).