Influence of Mooring Clump Weight on the Dynamic Responses of a Floating Offshore Wind Turbine Located in Shallow Water

Floating offshore wind turbines (FOWT) installed in shallow water depths require a clump weight to enhance the mooring restoring and platform motion stability. In order to obtain a rational design of mooring clump-weight, this paper investigates the dynamic responses of a FOWT with different clump weights under different environmental conditions using a well-validated fully coupled framework. The public-released WindFloat concept is improved to obtain a reliable design solution to support the 5 MW wind turbine. The motion and mooring tension of the 5 MW FOWT under the combined loadings of wind and wave are calculated. The influence of clump weights on the platform motion and mooring tension is qualitatively analyzed. The results show that the clump-weight is capable of reducing the platform surge for all examined load cases. More specifically, the average and maximum values of platform surge are reduced by 33.06% and 49.10% for a 65t clump-weight under 12 m/s wind condition. In addition, the clump-weight has a notable influence on the tension of the downwind moorings. The mooring tension can be doubled due to the presence of a clump-weight. Moreover, the platform motion and mooring tension change trends are almost the same under different wind speeds.