Effects of yaw on the wakes evolution of a wind turbine in wind tunnel

The wake effect of wind turbines in a wind farm has a significant effect on the back row of wind turbines. In order to study the effect of different yaw angles on the wake, two wind turbines were placed in a wind tunnel to form a small wind farm unit to measure the pressure distribution behind the wind turbine at different yaw angles, and the turbulence integration scale and power spectral density were used to describe the wake flow condition, then to analyze the effect of yaw angle on the wake field behind the wind turbine. The results show that the effect of yaw angle on the horizontal wake is small and the turbulence integration scale does not change much, while the turbulence integration scale in the vertical direction has large fluctuations under different yaw angles. The contribution of the vortex motion in the wake field to the turbulent kinetic energy of the wake is further depicted by the analysis of the velocity power spectrum. As the yaw angle increases, the damage to the wake structure increases. However, the damage caused by the yaw angle is limited, with the wake suffering less damage at 30° yaw than at 15°.