Predicting large-scale recirculation using a hybrid lidar-LES approach

Flow recirculation and other complex flow phenomena occur frequently in complex terrain. These phenomena cause high turbulence, and can impose high loading and maintenance costs to exposed wind turbines. It is known that most flow modelling tools fails to predict the presence or behavior of these phenomena. Approximations such as the Reynolds Averaged Navier-Stokes approach used in most comercial CFD tools actually suppress these large scale turbulent fluctuations. In order to better describe and predict recirculation and high-turbulent spots, a hybrid lidar-LES approach has been developed. The method has been tested in a full scale experiment in very complex terrain in a planned wind farm in Norway.