Large Eddy Simulation of wind farm aerodynamics : a review

To study wind farm aerodynamics (WFA), the Wind Power industry currently relies on simple Engineering Models (EM) that simulate wind farms using basic principles of physics and empirically established approximations. EMs are fast and accurate for an overview of WFA and gauging mean power production, but cannot resolve phenomena like wake meandering, effect of atmospheric stratification on wake development, a turbine¿s response to partial wake interaction and yawed inflows etc., and their relation with turbine loading, which require a first principle physics-based model, namely Computational Fluid Dynamics (CFD). Although advances in computer technology have promoted the application of CFD, the study of WFA is yet unworkable with Direct Numerical Simulation, which is the most comprehensive CFD technique. Thus, as a trade-off between cost and detail, researchers must resort to Large Eddy Simulation (LES) to garner thorough knowledge of WFA, which could in succession help the industry improve engineering models. This paper summarises the contributions of various LES investigations into WFA and how they have helped broaden our understanding of the subject. Additionally, the article touches upon the optimal use of LES and of the resultant data, and also the challenges faced by LES. Keywords: Large Eddy Simulation; Engineering models; Wind farm aerodynamics; Atmospheric boundary layer; Subgrid stress mode