Aeroelastic instability of ultra-long flexible blades in floating offshore wind turbines: A state-of-the-art review

Large-scale floating offshore wind turbines (FOWTs) represent the core equipment for deep-sea wind energy exploitation. Under the combined influence of wind, waves and currents, the ultra-long flexible blades face significant aeroelastic challenges. The blade dynamic response is highly coupled with the floating platform’s motion, resulting in prominent three-dimensional unsteady flow and complex modal coupling, which pose substantial difficulties for stability analysis and system design. This paper provides a systematic review on the progress in aeroelastic analysis methods, instability mechanisms and suppression strategies for ultra-long flexible blades of FOWTs. First, the unsteady flow features near the wind turbine and their evolution under the influence of platform motion are elucidated. Second, the aero-structural-hydrodynamic coupled modeling methods are summarized, comparing the advantages and limitations of Blade Element Momentum (BEM) theory, Free Vortex Method (FVM), and Computational Fluid Dynamics (CFD). Furthermore, the induced mechanisms of typical aeroelastic phenomena, such as classical flutter, stall flutter, vortex-induced vibration (VIV), and turbulent buffeting, are analyzed with a focus on their unique characteristics within floating systems. Finally, strategies for suppressing the aeroelastic instability of blades based on structural or flow control are summarized, and future research directions, such as high-fidelity coupled simulation methods and intelligent vibration suppression technologies, are proposed.