Large Eddy Simulation of Wind Events Propagating through an Array of Wind Turbines

Large-eddy simulation has been used to model the atmospheric boundary layer flowing through a span-wise periodic array of wind turbines. The wind turbines are modelled using a coupled simulation in which the FAST wind turbine simulation code from NREL operates within a CFD environment. The wind turbines are implemented in the flow-field using the actuator sector technique, and operate dynamically with pitch and yaw control. The development of wind event models for a CFD flow domain is discussed. The cases of a gust event and direction change passing through the farm is simulated, with the resulting flow field through the turbine array and turbine performance examined. The gust model simulations show the propagation of the structure through the array and its resulting dispersion due to the turbine wakes and ambient turbulence. Results from the wind shift simulations show a coherent wind shift front propagating through the domain at the free-stream wind-speed and the action of the yaw controller.