Vol 78 No 1 78104

Abstract

Wind-wave misalignment significantly affects the dynamic responses of floating offshore wind turbines (FOWTs). A fully coupled aero-hydro-mooring numerical model was established in OrcaFlex for a FOWT with a three-line shared-anchor mooring system. The numerical analysis evaluated three representative sea states (LC1, LC2, and LC3) alongside multiple wind-wave heading combinations. The six-degree-of-freedom (6-DOF) motion responses of the floating platform were systematically investigated using motion trajectories, kernel density estimation (KDE), violin plots, and probabilistic statistical analyses. The results indicated that: (1) the motion responses of the floating platform were jointly governed by the sea state and wind-wave heading. The sea state primarily determined the response intensity and variability, whereas the wind-wave heading governed the motion pattern. Increasing wind-wave misalignment angle shifted platform motion from unidirectional response to multidirectionally coupled motions. This shift led to increasingly dispersed probability distributions. (2) Different motion degrees of freedom exhibited distinct environmental sensitivities. Roll and pitch were primarily controlled by the wind direction, whereas relative wind-wave heading dictated yaw sensitivity. Increasing sea-state severity significantly amplified motion responses without altering their directional response characteristics. (3) Variations in platform motions altered shared-anchor loading characteristics. Higher wind-wave misalignment shifted shared-anchor loads from unidirectional to multidirectional distributions. Consequently, mooring lines underwent continuous load redistribution. These findings clarified the coupled effects of wind-wave misalignment on floating platform motions and shared-anchor loading. This work provides theoretical guidance for designing and assessing shared mooring systems in FOWTs.