LES of a wind turbine in the atmospheric boundary layer: parameter studies on inflow conditions

Large-eddy simulations are conducted with the geophysical flow solver EULAG for the flow through a wind turbine in differently generated turbulent atmospheric fields. The created wake in atmospheric precursor simulations for a stable boundary layer and an evening boundary layer, as well as in the synthetic model of an atmosphere, is investigated. The synthetic model of a neutrally stratified atmosphere is adapted to the characteristics of the present atmospheric simulation of an evening boundary layer in order to minimize the differences in these inflow conditions. While the adaption of the velocity of the synthetic model to the atmospheric simulation reduces the discrepancies in the calculated wake, the adaption of the turbulence intensity brings no superior approximation. The different inflow conditions for the LES of a flow through a wind-turbine are compared in regards to their streamwise wind profile the atmospheric spectra and the distribution of the turbulence intensity in the atmosphere. The properties of the turbulent structures in the models influences strongly the near wake, while the inflow velocity is mainly affecting the shaping of the far wake. The differences of neutral and stable stratification in the inflow fields lead to wide disparity in the generated wake