Experimental study of yawed inflow around wind turbine rotor.

In this article, we present an experimental study in a wind tunnel of a three-bladed, Rutland 503 model, horizontal axis yawed wind turbine. Power measurement and an exploration downstream wake of the turbine using particle image velocimetry measurements are performed. The variation of power coefficient as a function of rotational velocity is presented for different yaw angles. The results show a loss of power from the wind turbine when the yaw angle increases. The velocity field of the downstream wake of the rotor is presented in an azimuth plane, which passes through the symmetry axis of the rotor. The instantaneous velocity field is measured and recorded to allow for obtaining the averaged velocity field. The results also show variations in the wake downstream due to decelerating flow caused by the yawed turbine rotor. Analysis of this data shows that the active control of yaw angles could be an advantage to preserve the power from the wind turbine and that details near rotor wake are important for wake theories and to predict the performance of wind turbines as well. [ABSTRACT FROM AUTHOR]