Numerical investigation of wave-current-vegetation interaction

A fully three-dimensional numerical model has been developed to simulate the wave-current-vegetation interaction phenomenon. Physical experiments have also been carried out to provide data for the verification of the model. The numerical model utilizes the split-operator approach, in which the advection, diffusion, and pressure propagation are solved separately. Vegetation is modeled as a sink of momentum. The unsteady fluid force on vegetation is split into a time-dependent inertia component and a drag component. The model has been applied to simulate vegetation under pure waves, pure current, as well as wave current. Compared to available experimental, data, the model is capable of reproducing the turbulence and velocity profiles induced by vegetation-current interaction. The wave attenuation due to vegetation is simulated correctly with a proper value of drag coefficient. Both the physical experiments and numerical simulations show that the interaction of waves and current leads to a greater attenuation of waves in the presence of vegetation, which can be explained by the nonlinear nature of the resistance force induced by the vegetation.