A 3D acoustic propagation model for shallow waters based on an indirect Boundary Element Method

TL;DR

This paper introduces a 3D acoustic propagation model for shallow waters using a Boundary Element Method with a half-space Green function, validated through numerical tests and comparisons with known waveguide solutions.

Contribution

The work presents a novel formulation of a 3D acoustic model employing a half-space Green function within a Boundary Element Method framework, including initial numerical implementation and validation.

Findings

Model accurately predicts acoustic fields in idealized cases.

Using a bounded mesh yields acceptable accuracy for target regions.

Half-space Green function enhances modeling of shallow water acoustics.

Abstract

The purpose of this work is twofold: (a) To present the theoretical formulation of a 3D acoustic propagation model based on a Boundary Element Method (BEM), which uses a half-space Green function in place of the more conventional free-space Green function and (b) to show a numerical implementation aimed to explore the formulation in simple idealized cases --controlled by a few parameters--, and provides necessary tests for the accuracy and performance of the model. The half-space Green's function, which has been used previously in scattering and diffraction, adds terms to the usual expressions of the integral operators without altering their continuity properties. Verifications against the Pekeris waveguide suggest that the model allows an adequately prediction for the acoustic field. Likewise, numerical explorations in relation to the necessary mesh size for the description of the water-sediment interface allow us to conclude that a TL prediction with acceptable accuracy can be obtained with the use of a bounded mesh around the desired evaluation region.