On the Effects of the Change of Wind Direction to the Dynamical Property of a Wind Turbine

We experimentally and numerically studied on the dynamical property of a wind turbine of a blade having fixed-pitch angle to the change of wind direction. We assumed that the aerodynamic properties of the blade were given by a torque coefficient, which was measured in constant wind speed. We also assumed that the coefficient was a function of a tip speed ratio only. Averaged power was found to depend on the cube of cosine of yaw angle. Thus, change of yaw angle can be regarded as the change of wind speed upstream. We got an expresSiOn for the phase difference between wind and power variation as a function of the ratio of the variational frequency to a characteristic frequency. The behavior of wind turbine to the change of yaw angle showed glasses frames-like figure, and was numerically reproduced.