Flow characteristics analysis and power comparison for two novel types of vertically staggered wind farms

Reducing the wake effect to improve the power output of wind farms is identified as one of the grand challenges in wind energy science. To solve this problem, the windbreak and vertical axis wind turbine are added to the traditional aligned wind farm to form two novel types of vertically staggered wind farms (VSWF). A careful investigation is conducted to find the effect of crucial parameters on the power output and flow characteristics of proposed VSWFs. Results show that windbreak and VAWT both benefit the recovery of upstream wind turbine wake due to the mixing of wind flow and reducing wind shear, which increases the power output of VSWFs. Moreover, the power growth rate of VSWFs increases with the spacing. An interesting finding is that the larger tilt angle of the windbreak weakens the clockwise rotating vortex in the wake of the windbreak and increases the power output of the VSWF. Another important finding is that the power output of VSWF with VAWT is much greater than that of the windbreak, whose growth rate can achieve 13.1% (when LV = 6D). A possible explanation is that VAWT provides better wind penetrability and reduces surface roughness.