Wave Diffraction by Detached Breakwater

Abstract

A thin barrier of finite length in water of finite depth and infinite extent is considered. An incident gravity wave, attacking the obstacle from infinity, is diffracted and scattered by the thin barrier, which is a satisfactory representation of a detached breakwater of large length to thickness ratio. The aim of the work is to compute the waves potential energy (i.e., the wave height) in the region surrounding the obstacle. The maps of the state of the sea near the barrier permit a sound evaluation of the breakwater performance and henceforth an improved design. The computations are carried out first for a monochromatic incident wave and an impervious obstacle. The solution is extended afterwards to the cases of a pervious barrier and a random incident wave. The solution is compared with Wiegel's work (1963) on a barrier of semi-infinite length, with Morse and Rubenstein study (1938) of scattering of electromagnetic waves and Montefuso work (1968) on wave diffraction by an impervious barrier.