Fully coupled aero-hydrodynamic analysis of floating vertical axis wind turbines in staggered configurations

Floating vertical axis wind turbines (VAWTs) present a promising alternative to traditional horizontal axis wind turbines (HAWTs), offering higher power density and potential reductions levelized cost of electricity (LCOE). However, the performance of floating VAWT arrays in real world marine environments remains poorly understood, hindering their commercial viability. This study introduces a novel, fully coupled aero-hydrodynamic simulation framework, based on dynamic fluid-body interaction (DFBI) theory, to resolve the complex interaction between aerodynamic wake interactions, platform motion, and hydrodynamic loads in staggered floating VAWT configurations. The framework integrates orthogonal experimental design (OED) to systematically evaluate key layout parameters (turbine spacing, inflow angle, and rotational direction) for staggered bottom-fixed VAWT arrays. The inflow angle emerges as the dominant factor, with optimized staggered configurations achieving a 5 % increase in power density over isolated turbines. Comparative analysis of tandem, parallel, and staggered configurations demonstrates that staggered arrays uniquely mitigate wake interference through enhanced flow channeling and accelerated wake recovery, outperforming tandem layouts (which suffer up to 11.8 % efficiency losses) and parallel arrangements (limited by spacing-dependent symmetry breakdown). For staggered floating systems, the framework incorporates six-degree-of-freedom platform motion, revealing that hydrodynamic-induced platform dynamics amplify performance indicator by 22 % compared to fixed-bottom counterparts. This synergistic coupling between aerodynamic wake effects and wave-driven platform oscillations highlights the necessity of holistic aero-hydrodynamic modelling for accurate performance predictions. The framework's predictive capabilities, validated against baseline cases, offer actionable insights for minimizing wake losses and maximizing energy yield in cost-sensitive marine environments. These advances position staggered floating VAWT arrays as a scalable, economically competitive solution for offshore wind energy expansion, directly addressing global decarbonization challenges.