NUMERICAL MODELING FOR WAVE ENERGY DISSIPATION WITHIN POROUS SUBMERGED BREAKWATERS OF IRREGULAR CROSS SECTION

Abstract

In the design of a porous submerged breakwater, the maximum wave energy dissipation within the breakwater is desirable. To calculate the energy dissipation, the process is simulated numerically in this study using the Boundary Integral Element Method (BIEM). The breakwater is idealized as a homogeneous porous medium and the flow inside the breakwater is modeled by a non-linear porous flow model which is linearized iteratively based on the equivalent energy principle in the numerical model. To fully explore the advantage of BIEM, a boundary integral expression for wave energy dissipation developed in an earlier work by the authors is used to replace the traditional domain integral expression. As a result, the efficiency of the numerical model is greatly increased. The numerical model was run for a number of cases and the results show that the maximum wave energy dissipation can be achieved at a practical permeability level (or stone size). The good agreement between the numerical results and the experiment data for non-breaking waves indicates that the wave energy dissipation within porous breakwaters can be adequately predicted by the numerical model.