Study on the Motion Suppression Effect of Point Absorber Arrays Integrated with Floating Wind Turbines Using CFD Simulation

Journal article, 2026

Large-amplitude pitch motions in floating offshore wind turbines (FOWTs) not only degrade aerodynamic performance but also heighten the risk of structural instability and blade-tower collisions, thereby hindering their deployment. Integrating wave energy converters (WECs) with FOWTs enables wave energy harvesting and motion stabilization. However, conventional potential flow methods have inherent limitations in representing viscous effects and strong nonlinearities, which may limit their ability to fully resolve the mechanisms governing WEC-induced motion responses. To address this challenge, this study develops a computational fluid dynamics (CFD) model to resolve the coupled dynamics of the hybrid wind-wave (HWW) system. The relative motion between the FOWT and the WECs is captured through a motion superposition technique. A morphing-overset mesh strategy is employed to simulate large-amplitude motions and preserve mesh quality near moving bodies. Nonlinear mooring responses are incorporated by directly coupling with MoorDyn through a C++ interface. The present model allows a detailed investigation of the influence of WEC integration on the flow field and its further effects on platform dynamics, mooring tension, and power generation. The results show that integrating WECs effectively suppresses platform pitch by reducing fore-aft pressure differentials and enhancing restoring moments. However, excessive power take-off (PTO) damping can amplify wave diffraction and shadow effects, partially offsetting this benefit. A trade-off is identified between energy capture and platform dynamics, whereby slightly lower PTO damping than the power-optimal value yields comparable WEC power output while achieving significantly greater reductions in pitch motions and mooring tension. In addition, submerging the WECs is shown to improve system survivability by mitigating surge motions and reducing mooring loads. Overall, these results provide insights into the coupling mechanisms of HWW systems and support the development of effective motion mitigation strategies for floating wind turbines.