High-Resolution Offshore Wake Simulations with the LES Model PALM

Large-eddy simulations of wind turbine wakes have been performed with the LES model PALM. A comparison of the implemented actuator disk and actuator line models shows differences in the near wake which diminish in the far wake several diameters downstream of the rotor plane. Furthermore, the results of wake simulations with different inflow boundary conditions are presented. The major drawback of cyclic horizontal boundary conditions, which are often used for wake simulations, is that the inflow used will be the one already modified by the wind turbines. With non-cyclic boundary conditions and a laminar inflow, the inflow remains undisturbed and constant in time. However, a very large model domain is required so that a turbulent flow can develop. The application of a turbulence recycling method results in a well developed turbulent boundary layer already at the inflow so that the model domain can be significantly reduced.