Wave Load Prediction Methods in Offshore Wind Turbine Modelling and their Influence on Fatigue Load Analysis

The optimization of offshore wind turbines requires a design against extreme loads as well as fatigue loads. The latter is supposed to be more sensitive to a correct sea state modelling. Hence, wave load prediction methods with and without regarding the waves’ directionality and spreading have been investigated with respect to their impact on damage equivalent fatigue loads. Simulation results have been compared with strain measurements at two different structures located in the North Sea. Finally, the consideration of the waves’ directionality results in an approximate reduction of observed forces of up to 20% compared to the unidirectional approach.