Visco-elastic-plastic model for muddy seabeds

A numerical model of the interaction between waves and a muddy seabed was developed to study wave attenuation by the muddy seabed. The governing equations for both the water and the mud were the continuity equation and the equation of motion for incompressible fluids. The water was treated as a Newtonian fluid. A viscous fluid model and a visco-elastic-plastic model were used to describe the rheology of the seabed. The finite volume method was used to solve the governing equations, and both the free water surface and the interface between the water and the mud were tracked by the VOF method. Wave attenuation by the muddy seabed was investigated for various seabed densities. The viscous fluid model performs well for the low density mud, but when the mud density is relatively large the plasticity of the mud plays an important role in the wave attenuation. Thus, the visco-elastic-plastic model should be used for the mud.