Wave Transmission by Rectangular Submerged Breakwaters

Abstract

In this paper, we investigate the wave damping mechanism caused by the presence of submerged bars using the Shallow Water Equations (SWEs). We first solve these equations for the single bar case using separation of variables to obtain the analytical solution for the wave elevation over a rectangular bar wave reflector with specific heights and lengths. From the analytical solution, we derive the wave reflection and transmission coefficients and determine the optimal height and length of the bar that would give the smallest transmission coefficient. We also measure the effectiveness of the bar by comparing the amplitude of the incoming wave before and after the wave passes the submerged bar, and extend the result to the case of n-submerged bars. We then construct a numerical scheme for the SWEs based on the finite volume method on a staggered grid to simulate the propagation of a monochromatic wave as it passes over a single submerged rectangular bar. For validation, we compare the transmission coefficient values obtained from the analytical solution, numerical scheme, and experimental data. The result of this paper may be useful in wave reflector engineering and design, particularly that of rectangle-shaped wave reflectors, as it can serve as a basis for designing bar wave reflectors that reduce wave amplitudes optimally.

Field Observation and Quasi-3D Numerical Modeling of Coastal Hydrodynamic Response to Submerged Structures

“…determined by the location and dimensions of the structure (width and crest height of SBWs) as well as incident waves from the open sea, which are major factors that cause the advance and retreat of the coastline. However, they had limitations in spatially observing complex phenomena that occur around SBWs comprehensively, with studies actively conducted worldwide on the development and advancement of numerical modeling techniques to evaluate the changes in waves, currents, and topography caused by the installation of SBWs in advance (Johnson et al, 2005;Liang et al, 2015;Magdalena et al, 2020;Quataert et al, 2020). However, previous studies reproduce the coastal flow, sediment transport, and topographic changes caused by SBWs through a 2D precision model to simulate the attenuation of the waves caused by SBWs and a planar model based on water depth integration and wave-governing equations.…”