Analysis of water wave interaction with a flexible submerged perforated semi-circular breakwater

Abstract

Abstract This study examines the hydroelastic interaction between water waves and a flexible submerged perforated semi-circular breakwater based on linear potential theory. The breakwater is idealized as a bottom mounted perforated semi-circular Euler–Bernoulli beam with constant elasticity. The boundary condition on the flexible beam is derived from the equation of motion of the semi-circular beam, which is developed by the principle of virtual work. An analytical solution for wave interaction with the flexible breakwater is developed using multipole expansions. Also a numerical solution using multi-domain boundary element method (BEM) is developed for validation of the analytical solution, where the beam displacement is expressed as an integral representation involving unknown dynamic pressure difference between both sides of the beam using Green function technique. The convergence of the analytical solution is very rapid, and a few truncated terms yield results with five order of accuracy. Agreement between the analytical and numerical solutions is excellent. Features for hydrodynamic quantities of the flexible breakwater are examined by presenting typical calculation examples. Valuable results are drawn for engineering design of flexible structures.