Numerical Simulation of Large Scale Wind Turbine Wake and the Influence on Vibration of Downstream Wind Turbine

In order to investigate the wake evolution law of large scale horizontal axis wind turbine and its influence on vibration of downstream wind turbine, large eddy simulation method has been used to study the single wind turbine with a capacity of 5.5 MW and the tandem double turbines respectively in this paper. The results of single wind turbine wake show that the average velocity distribution law of wake fits well with the prediction results of two-dimensional engineering wake empirical model named 2D-k-Jensen. The wake development and evolution process has been observed by the flow field diagram. In addition, it is observed that the wake deflects 0.82° relative to the incoming flow direction under the condition of 0° yaw angle. The results of wake influence on downstream wind turbine show that the thrust main frequency of downstream wind turbine in 3D position of upstream wind turbine wake coincides with the 3P frequency of its operation. At the same time, combined with a large amount of wind farm tests data analysis, there is a high correlation between the vibration frequency of wind turbine and its 3P frequency, which determines that the wake can cause the wind turbine vibration.