Effects of a multi-segment mooring system using buoy and clump weights on motions of the OC-4 DeepCwind wind turbine system under wind and waves

Abstract

Hybrid mooring systems have gradually shown a good effect in reducing platform movement in recent research. A multi-segment mooring system using buoy and clump weights (MSM-BMW) is one of the hybrid mooring systems. To clarify the difference between MSM-BMW and a catenary mooring system for the OC-4 DeepCwind wind turbine system under different wind and wave conditions, this paper uses the FAST linked AQWA fully coupled framework (F2A) to investigate the motion response and mooring force of the wind turbine platform with two different mooring systems. The validations indicate that the parameters of the platform are reasonable and F2A tool is good. The sea conditions are designed based on the South China Sea, including wind-wave misalignment, wave-only, wind-only and wind-wave. The results indicate that MSM-BMW reduces the impact of changes in wind and wave directions on the motion response of the platform. High-frequency resonance in the mooring force of MSM-BMW is related to the wind and wave directions, and the wind loads can reduce the resonance. As for the OC-4 DeepCwind wind turbine system, MSM-BMW outperforms the catenary mooring system in the motion response and decreases the low-frequency response under wind-wave misalignment and wind-dominated.