Evaluation of a low-fidelity hydrodynamic modelling approach for a floating wind turbine mounted on an enhanced spar

The present work revolves around the numerical simulation of floating offshore wind turbines, a promising technology for energy harnessing in deep water conditions. A reference 10MW wind turbine is studied, mounted on a commercial enhanced spar buoy, referred to as the WIND-bos platform. The focus is put on the hydrodynamic modeling. In particular, the Morison equation is used, accounting for a fixed set of coefficients. Those coefficients are initially estimated based on the literature, and subsequently calibrated through the comparison with experimental results on a scaled geometry. This allows to assess the modeling capabilities of the Morison approach, together with its challenges and limitations. Larger discrepancies between the numerical model and the experiments were assumed to be related to the geometrical particularities of the floating platform. In particular, the studied structure accounts for both large and slender members, potentially limiting the applicability of the method. It is shown that the deviations could be attributed to the frequency-variation of parameters such as the added mass, the radiation damping and viscous damping. Therefore, it is concluded that the agreement between the numerical model and the experiments could be improved by re-calibrating the coefficients for each of the studied sea states.