Yaw and tilt wake characteristics of horizontal axis wind turbine

The wake interference of wind turbines is the main factor affecting the performance and output of wind turbines downstream of the wind farm. By adjusting the attitude of the wind turbine, the wake interference effect can be effectively improved, but it also introduces more complex unsteady aerodynamic characteristics and wake field distribution. In order to study the wake characteristics of wind turbine attitude control, based on the lifting-line and free vortex wake model, the aerodynamic wake model of the horizontal axis wind turbine is established. Taking the NREL 5MW wind turbine as the research object, under the condition of rated wind speed, the wake characteristic of the turbine under yaw and tilt conditions is studied. The wake disturbance of the wind turbine yaw and tilt condition under the influence of wind shear and tower is further analyzed. The results show that, yaw and tilt will cause the instability of the wake vortex structure in advance, the turbulence intensity in the far wake region will increase, the wake center will deflect and the wake action area will decrease. In addition, yaw and tilt will accelerate the recovery of velocity deficit and reduce the interference of wake effect on the downstream. Wind shear will exert a similar effect on the tilt of the wind turbine, which will raise the wake and reduce the area of wake. The interference of the tower to the near wake region is more significant, and the tilt control will reduce the interference of the tower to the wake.