Analysis of wake recovery effects using small-diameter-ratio wind turbines for vertically staggered wind farms

The optimization of the layout wind farms to reduce the wake effect and increase the output power of wind farms has been a challenge for the wind energy science community. To solve this problem, we propose a method of wake forced recovery based on a small horizontal axis wind turbine (SHAWT). In this paper, the effects of key parameters such as relative distance (L), relative height (H), and number of SHAWT on the output power and flow characteristics of a vertically staggered wind farm (VSWF) are carefully investigated. The results show that this method of forced wake recovery has a positive impact on the output power of the overall VSWF. Meanwhile, we found that the effect of SHAWT on VSWF increased with an increase in L. When L = 6D, the downstream wind turbine output increased by 10.93%. When the H value is larger than its optimal value, continuing to increase H will reduce the output power of the downstream wind turbine. In addition, by studying the number of SHAWTs, we found that increasing the number of SHAWTs is detrimental to the wake recovery of the upstream turbines. On this basis, this paper also explores the applicability of SHAWT under real wind farm boundary conditions (wind shear, turbulence intensity, and rotational speed).