Developing an OpenFOAM solver for coupled aero-hydrodynamic analysis of integrated structure with floating offshore wind turbine and aquaculture net cage

The integrated structure of floating offshore wind turbines (FOWTs) and aquaculture net cages has garnered significant attention in recent years. This study establishes, for the first time, a CFD analysis method for the integrated structure of FOWTs and aquaculture cages, and develops a specialized solver, HybridMarineFoam, for coupled analysis of the integrated structure. The solver currently includes aerodynamic, hydrodynamic, mooring, and aquaculture cage computation modules. The aquaculture cage module is based on the Darcy-Forchheimer model, incorporating the influence of the floating platform's motion into the Darcy-Forchheimer equation and accounting for the hydrodynamic impact of the cage on the floating platform, thus achieving coupled calculations between the fish cage and the floating platform. In this study, the force loading calculation for the moving aquaculture cage and the coupling simulation for the integrated structure have been very well validated. Subsequently, an integrated structure, combining an IEA 15 MW FOWT and an aquaculture cage, was proposed, and the HybridMarineFoam solver was used to analyze its aerodynamic, hydrodynamic, and flow field characteristics under different wind speeds, wave heights and water current speeds. The results reveal that the presence of the cage significantly impacts the system dynamics motion response and flow field characteristics of the floating wind turbine.