On the impact of wind farms on a convective atmospheric boundary layer – a large-eddy simulation study

We integrate three-dimensional large-eddy simulations (LESs) with an actuator disk model with rotation (Wu and Porté-Agel, 2010) to investigate the impact of wind farms on a convective boundary layer (CBL). The wind turbines, with a rotor diameter of 93m and a tower height of 80m, are “immersed” in the CBL case that includes fixed geostrophic wind on the top, uniform heating on the ground and the Coriolis effect, and bears a boundary layer height of approximately 800m. In order to understand spacing and layout effects, the LES framework is applied to study several cases of aligned and staggered wind farms with different streamwise and spanwise spacings. In line with wind farms in a stable boundary layer (Lu and Porté-Agel, 2011), results show that in the presence of wind turbines, the boundary layer height is increased, while the magnitudes of the surface momentum flux and the surface heat flux are reduced. These highlight the potential impact of wind farms on local meteorology. Moreover, the staggered configuration delivers larger momentum extraction (potentially more wind-energy power production); but, relatively, no significant differences in many other mean quantities.