Abstract: The dynamic response of seabed soil around tidal energy turbine foundations, under the combined action of waves and tidal currents, has become increasingly crucial with the continuous development and utilization of tidal energy resources. To deepen our understanding of the dynamic characteristics within the seabed near tidal energy turbines, we established a numerical model that considers the interaction between waves, tidal currents, seabed, and turbine foundations. The model incorporates the rotational effect of turbine blades, facilitating one-way coupling between the wave sub-model and the seabed sub-model through data exchange on the seabed surface. The Reynolds-Averaged Navier-Stokes (RANS) equations were employed to control the nonlinear fluid motion, while Biot’s theory equations to describe the interaction between the solid and fluid phases in the porous medium. By using this model, we examined the wave-induced responses of surrounding soil of tidal energy turbine’s monopile foundations, and analyzed the soil liquefaction risks under wave action. Simulation results reveal that the rotation of water turbine blades amplifies the wave pressure in front of the pile by 75%, increases the wave height behind the pile by 25%, induces a 24% increase in pore pressure caused by the waves, elevates the yz shear stress by 230%, and enhances the liquefaction depth of the soil behind the pile by 50%.

Key words: monopile foundation, wave-current action, tidal stream turbine, OpenFOAM, seabed dynamic response