The upscaling of floating offshore wind turbines (FOWTs) introduces pronounced fluid–structure interaction effects, challenging the applicability of rigid-rotor assumptions in aerodynamic and wake predictions. This study develops a partitioned computational fluid dynamics–finite element method (CFD–FEM) framework integrated with Dynamic Fluid Body Interaction to investigate the aero-hydro-elastic response of a 15 MW FOWT under combined wind–wave excitation. By comparing rigid- and flexible-blade configurations, the effects of blade compliance on aerodynamic loading, platform kinematics, local inflow modulation, free-surface response, and wake evolution are examined. Under the H8 condition, blade flexibility attenuates the wave-frequency thrust fluctuation by 22.1% and reduces the peak-to-peak platform pitch response by 12.2%. Sectional kinematic reconstruction shows that the flapwise deformation velocity modifies the local relative inflow and moderates the reconstructed effective angle of attack, thereby reducing the suction-side pressure loading at the analyzed blade section. The free-surface analysis further suggests that this aeroelastic load-alleviation response reduces the body-relative transient run-up around the upwind column. In the wake, the flexible-blade case exhibits an earlier loss of coherent helical-vortex organization and a faster recovery of the mean velocity deficit at the intermediate-wake measurement plane. These observations are consistent with enhanced macroscopic momentum exchange between the ambient flow and the wake core. The findings highlight the importance of incorporating blade flexibility in blade-resolved coupled CFD–FEM simulations of ultra-large FOWTs, particularly for predicting unsteady aerodynamic loading, platform response, local free-surface elevation, and downstream wake evolution.
Wang et al. (Mon,) studied this question.