Large-eddy simulations (LES) for far-wake effect modelling of offshore wind farms

The construction of Germany’s offshore test site “alpha ventus” situated 45 km north of the island of Borkum marks the starting point of large-scale exploitation of offshore wind resources in German waters. Therefore, extensive Research at “Alpha VEntus” (RAVE) is funded by the German Federal government. One of the aims of this research is the verification of essential aspects in the design and operation of offshore wind turbines (OWEA project). Besides measurements also numerical simulations of the flow conditions in offshore wind farms will be carried out. Here, we report on the development of a large-eddy simulation (LES) model that will finally be applied for simulations of flow conditions within and in the surrounding of the “alpha ventus” test site. Results of a first validation of the new LES tool against previously published LES results and measurements for the wake of a single wind turbine are presented. Our results are in good qualitative agreement with earlier published results. Quantitative differences to the measured wake flow might be related to the fact that the actuator disc model used does not take into account the rotation of the flow behind the wind turbine.