Numerical investigation of the coupled aero-hydro-mooring dynamics of a floating offshore wind turbine under slope-induced wave breaking conditions

Wave breaking is one of the most destructive ocean phenomena for floating offshore wind turbines (FOWTs), yet its influence on the dynamic response and overall performance of FOWTs remains unclear. In this study, a high-fidelity computational framework based on OpenFOAM is developed to model wave shoaling and breaking, as well as the coupled aerodynamic, hydrodynamic, and mooring responses of a FOWT. The responses of the FOWT under breaking-wave and non-breaking-wave conditions are systematically analyzed and compared. The results show that compared with the non-breaking case, the peak horizontal wave force in the breaking-wave case increases by 53.4%. The maximum hydrodynamic pressure is approximately twice that under non-breaking conditions. The surge and pitch motions increase by 6.07% and 5.23%, respectively, while the heave oscillation is suppressed. It is also found that breaking waves can increase the maximum fluctuation amplitude of the thrust coefficient by 206.08% and accelerate the wake transition through earlier breakdown of coherent tip vortices. In addition, the maximum windward mooring tension increases by 13.7%, while the downstream tension decreases by 28.8%. The present study establishes a computational framework for FOWTs under breaking wave conditions and provides new insights into the nonlinear response mechanisms of FOWTs under breaking waves.