By using our sharp interface two-phase model, we present some results for problems involving the fluid-body coupling in the ocean environment of the wind, wave and current effects. The model is based on a highly efficient Navier-Stokes solver, constructed by a novel VOF finite volume cut-cell approach that incorporates surface tension and a dynamic subgrid-scale model. Grid refinement studies are performed for test problems involving overtopping of waves over a seadike. Additionally, we study the effects of a current on the wave-body coupling in winds. The immersion ofmodel-scale tunnel elements is also investigated in winds, waves and currents. The measurements available are used for validation of our computations. Hopefully, the results can provide a valuable base for the design of offshore wind structures.
Typically, the analysis of flow mechanics of the fluid-body coupling in the wind-wave environment at sea is essential to industrial needs for improved and cost-efficient design of offshore wind structures. The study helps to illustrate higher-harmonic loads, for example, over a vertical structure fixed in the shallow water environment. Of particular interest is the velocity fields, as well as high-harmonic forces, that occurs in very strong waves, especially under wind and current effects. Physically, such feature may induce vibrations of the structure eigenperiods, resulting in serious damages to structures, as one extreme case of the most frequent causes of structural failure. Owing to breaking waves, the flows are subjected to rapid free-surface deformation and surface-vortex coupling, including air-flow separation. Importantly, the additional effects of winds substantially aggravate the situation that may change the environments, as the combination of extreme wind, wave and current conditions is used to establish the design loads for large offshore structures. Consequently, the investigation is an essential in engineering and desirable to elucidate mechanism at the fundamental level.