A review of fluid–structure interaction modelling for integrated analysis of floating offshore wind turbine substructures

Floating offshore wind turbines (FOWTs) are advancing toward larger-capacity with novel structural designs aiming at lowering the levelized cost of energy (LCOE). FOWTs are required to withstand a large and diverse set of dynamic loads throughout their operational lifetime. Consequently, a rigorous assessment of their performance via a physics-based coupled engineering model is essential during their design stage. Despite continued advances in modelling tools, challenges in modelling hydro-structural interaction in coupled aero-hydro-servo-elastic simulations for large FOWTs remain. This paper provides a state-of-the-art review of the recent advancements in modelling techniques for coupled hydrodynamic and structural analyses of floating wind turbines considering mid-fidelity engineering models using aero-hydro-servo-elastic tools (e.g., OpenFAST). Key focal point is numerical treatment of hydro-structural interactions, highlighting rigid multibody and flexible-body approaches, together with experimental advancements for validating these numerical models. This review demonstrates that both rigid multibody and flexible-body substructure approaches have been implemented and validated within a few time-domain coupled engineering models. Broader expansion to various hydro-aero-servo-elastic tools, particularly with standardized procedures, is essential to meet the demands of future-generation floating offshore wind turbines.