Wave Characteristics over a Dual Porous Submerged Breakwater Using a Fully Nonlinear Numerical Wave Tank with a Porous Domain

Abstract

This study developed a two-dimensional fully nonlinear numerical wave tank (FN-NWT) to examine the nonlinear interaction between waves and dual submerged porous structures. Using the FN-NWT, not only reflection and transmission coefficients, but also wave deformation/force depending on porosity were investigated. The FN-NWT was developed using the boundary element method (BEM), and consisted of a fluid domain and a porous medium domain. Darcy’s law or the non-Darcy (Forchheimer) flow equation were applied to the flow passing through the porous domain. The wave reflection coefficient of the porous submerged structures agreed well with the given experimental data when using Forchheimer flow boundary conditions. Excessive attenuation of the transmitted wave occurred when Darcy’s condition was employed. The difference in each coefficient due to the spacing of the submerged structure was reduced in the porous structure compared with the non-porous structure. The difference according to the incident wave height was clearly revealed in the transmission coefficient. The developed dual-domain FN-NWT can be applied to investigate the nonlinear interaction between waves and porous structures as a first-cut design tool.

Optimization Analysis of the Shape and Position of a Submerged Breakwater for Improving Floating Body Stability

“…Lee et al (2002) conducted an experimental and numerical study on the distribution of vorticity, turbulence, and wave height according to the density, width, and arrangement of submerged rigid vegetation. Min et al (2023) analyzed the reflection, transmission, and dissipation coefficients of dual submerged breakwaters using a fully nonlinear numerical wave tank (NWT) based on the boundary element method considering porous domain. They also conducted an analysis of the change in wave height caused by breakwaters and the pressure distribution inside permeable submerged breakwaters.…”