Influence of a bottom mud layer on the resistance of marine vehicles

The effects of the underlying sea bottom on the shallow-water hydrodynamic performance of marine vehicles are investigated. An upper layer of clean inviscid water over a viscoelastic mud layer lying on a rigid horizontal bottom was considered. The fluid domain was bounded by two vertical straight walls on each side to allow investigation of the effects of the channel walls. A generalized stress-strain relationship of the mud flow was considered, taking into account not only the viscosity and different density, but also the elastic properties of mud. A linear viscoelastic model which relates the shear stress to the rate of strain by a convolution type integral was also used.