NUMERICAL MOdeling of WAVE MOTION ON SUBMERGED BREAK WATER

This paper presents a numerical model for simulating wave interaction with porous structure and submerged breakwater. For permeable structures several aspects concerning the interaction between the external and internal flow have to be assumed accurately to predict correctly the variables such as velocities. A model has been developed for the wave motion on and in several types of coastal structures and gravel beach, on the basis of Kobayashi and Van Gent studies. These structures can be permeable or impermeable. The program takes various phonemena into account such as reflection, permeability, infiltraction, and seepage. This numerical model is similar to ODIFLOCS (One Dimensional Flow On and in Coastal Structures) that developed by Van Gent in 1992. For hydraulic part of the model, long wave equation have been used. Kobayashi et al. in 1987 has showed that long wave equations can be applied successfully for the wave motion on impermeable structures. He showed in 1991 that effect of permeability in porpous structure could not be ignored. The numerical model described here uses normal long wave equations (Eq.1) for the hydraulic part and the modified long wave equations (Eq.2) for porpous part of the model. The coupling of these two models (hydraulic and porpous) requires some attention for aspects like for instance the disconnection of the free surface and the phreatic surface.