ENERGY DISSIPATION OF WAVE-UNIFORM CURRENT OVER A RIGID POROUS MEDIA WITH FINITE THICKNESS

摘要

The linear wave theory and the nonlinear-unsteady porous flow model are applied to analyze the energy dissipation and the bed pore water pressure induced by the interaction of wave, uniform current and porous bottom without considering the nonlinear waves and the viscosity effect inside the boundary layer. In this model, the linear, inertial and turbulent resistances are combined into a linearized resistance coefficient and the present system can be analyzed by a linear boundary value problem. The numerical result is quite agreement with the existing experimental data. It shows that the energy dissipation is reduced by the Doppler shift and the distribution of energy loss moves to the lower relative water depth region in the wave-following current. On the other hand, the bed pore water pressure in the wave-following current is always lager than that in the pure wave and the wave-opposing current.