A boundary element model for underwater acoustics in shallow water

Abstract

Copyright © 2000 The Author(s). This work presents a boundary element formulation for two-dimensional acoustic wave propagation in shallow water. It is assumed that the velocity of sound in water is constant, the free surface is horizontal, and the seabed is irregular. The boundary conditions of the problem are that the sea bottom is rigid and the free surface pressure is atmospheric. For regions of constant depth, fundamental solutions in the form of infinite series can be employed in order to avoid the discretisation of both the free surface and bottom boundaries. When the seabed topography is irregular, it is necessary to divide the fluid region using the subregions technique. In this case, only irregular bottom boundaries and interfaces between regions of different depth need to be discretised.Numerical simulations of several problems are included, ranging from smooth to abrupt variations of the seabed. The results are verified by comparison with a more standard BEM formulation in which the complete seabed is discretised and truncated at a large distance.