Characteristics of wave run-up height on a sandy beach behind dual-submerged breakwaters

Abstract

Using a newly developed three-dimensional numerical scheme, we analyzed the characteristics of wave run-up height at a shoreline with various arrangements of dual-submerged breakwaters and the characteristics of wave height and surface-layer flow around dual-submerged breakwaters. Using our model, which considers wave-structure-sandy seabed interactions in a 3-D wave field, we were able to determine the direct effects of the porous media of submerged breakwaters and a sandy beach on the flow characteristics. A numerical analysis reveals that, when dual-submerged breakwaters are installed, the wave energy coming into the shore decreases because the waves break due to shoaling and the fluid resistance caused by the permeability of the submerged breakwaters. in addition, dual-submerged breakwaters reduce the wave height on the onshore side of the submerged breakwaters and the wave run-up height at the shoreline. The wave run-up height at the shoreline shows that, because of wave overlapping caused by the effects of wave refraction and diffraction behind the submerged breakwater, the wave run-up height at the shoreline behind the submerged breakwater is generally greater than that behind the open inlet. Further, the maximum wave run-up height appears behind the center of the submerged breakwater. (C) 2012 Elsevier Ltd. All rights reserved.