Effect of wind-waves misalignment on the dynamics and power performance of floating offshore wind turbines

Floating offshore wind turbines (FOWTs) are crucial for accessing deep-water wind resources, yet their operation is complicated by frequent wind–wave misalignments that affect stability and power performance. These misalignments stem from differing wind and wave generation mechanisms, including rapid wind-direction shifts and distant swells. This study evaluates the dynamic structural response and power performance of an FOWT under misalignment angles from 0° to 120° in increments of 30°. Results show that misalignment amplifies lateral and rotational platform motions, with sway and roll dominating at β = 90°–120°, while surge decreases with increasing misalignment. Tower-base pitch and yaw moments peak at β = 90°, indicating elevated fatigue risk. Power output decreases by up to 57% under extreme misalignment, with fluctuations stabilizing at higher β due to reduced aerodynamic efficiency. These outcomes emphasize the need to account for wind–wave misalignment in FOWT design, control strategies, and site-assessment practices. • Dynamic responses of FOWT are studied under wind-wave misalignment. • Lateral platform motions are amplified at 90–120°. • Maximum nacelle vibration and tower base moments appear at 90°. • Power output reduces by 46.98% under extreme misalignment.