An integrated modelling framework of a two-bladed floating VAWT based on two-way fluid–structure interaction

Abstract

Vertical-axis wind turbines (VAWTs) are increasingly regarded as promising alternatives for horizontal-axis configurations in large-scale floating wind systems. However, existing coupled modeling tools for floating VAWTs still present several limitations: simplified aerodynamic formulations, inviscid hydrodynamics, quasi-static mooring representations, and limited consideration of composite blade aeroelasticity, hindering accurate multi-physics prediction. To overcome these shortcomings, a comprehensive aero-hydro-elastic-mooring coupling framework is established in this study. The proposed approach integrates the finite element method (FEM) and the computational fluid dynamics (CFD) to resolve fluid–structure interaction considering turbulence, waves, and the integral floating VAWT system. The results show that platform motion intensifies the periodic development of leading-edge vortices and dynamic stall by altering the blade relative inflow velocity and effective angle of attack. Although this aggravates the fluctuations of instantaneous torque and power output, it also provides a positive compensating effect on the overall aerodynamic work, resulting in an approximately 6.46 % increase in the mean power coefficient of the floating configuration compared with bottom-fixed one. These platform-motion-induced wake deflection and enhanced turbulent mixing also accelerate recovery, potentially improving array efficiency. Furthermore, the coupled dynamic analysis investigates the nonlinear stress concentrations near the blade-strut, strut-tower, and platform main-column regions, and further reveals the bending-torsional coupled deformation characteristics of the flexible blades. Meanwhile, the mooring system undergoes periodic contact and separation from the seabed, which may induce local scour and fatigue accumulation. Overall, the proposed CFD-FEM framework provides a robust tool for aero-hydro-elastic performance evaluation and structural safety assessment of floating VAWTs, offering valuable guidance for aerodynamic design, integrated load management, and cost-effective offshore deployment.