Large-Eddy Simulation for Wind Turbine Fatigue Load Calculation in Forest Regions

Large-Eddy Simulations have been used for predicting theatmospheric boundary layer in neutral stability under the influence of a forest. The objective is to generate input fields for load calculations that accurately represent the flow conditions above forest regions. In the simulations, the forest is modeled in terms of an additional drag force in the lowest part of the domain. This forest model has proved to be working reliably and being versatile, as it is easily adapted to many different sorts of trees. Two different LES cases are considered in the present work: one regular LES that can be considered the baseline case and a LES with additional forcing from synthetic turbulence in the upper part of the canopy. The mean velocity profile is shown to agree well with measurements from a test site in southern Sweden for the forcing case. However, the forcing case is not able to predict the shear stress profile well