NUMERICAL SIMULATION OF WAVE OVERTOPPING OF A VERTICAL POROUS DETACHED BREAKWATER

Abstract

Various types of vertical porous detached breakwaters are being built to reduce the impact of wave pressure on sea dikes as well as avoid rapid, severe erosion along the coastline of the lower Mekong Delta area. Waves can both pass through the porous breakwater and over the top of the structure (overtopping). The effectiveness of porous structures varies because it depends on the crest freeboard height, breakwater width, and porosity. However, the effectiveness of this type of porous detached breakwater has yet to be proven. This paper evaluates the effectiveness of this type of breakwater by introducing a numerical model based on the Navier – Stokes equations applied to the porous media. The numerical model is applied to simulate solitary waves interacting with the porous structures for various cases. The numerical results show that when the crest freeboard is low (low-crested porous breakwater), the breakwater width and the porosity of the breakwater do not significantly affect the wave height behind the breakwater. The wave reduction effect is greatly increased with the increase of the crest height due to submerged breakwater and overtopping waves. The breakwater schematization is tested to show the porous breakwater effectiveness in reducing wave energy.