**4. Wind energy applications**

With the fast growing number of wind farms being installed worldwide, the interaction between ABL turbulence and wind-turbine wakes, and its effects on energy production and dynamic loading on downwind turbines, have become important issues in the wind energy and atmospheric sciences communities [92]. Optimizing the design of wind energy projects (placement of isolated wind turbines or layout of wind farms) requires the prediction of atmospheric turbulence and its interactions with wind turbines at a wide range of spatial and temporal scales. As a result, during the last decade, numerical modeling of wind-turbine wakes has become increasingly popular. Most of the previous studies of ABL flow through isolated wind turbines or wind farms have parameterized the turbulence using a RANS approach [3, 4, 30, 42]. Only recently there have been some efforts to apply LES to simulate wind-turbine wakes [16, 36, 37, 59, 78, 97]. In addition to the above-mentioned challenges in LES of the ABL, the accuracy of LES for wind energy applications hinges also on our ability to parameterize the forces induced by the turbines on the flow. These forces are responsible for the development of the turbine wake.
