Acoustic propagation modeling in environments which induce horizontal refraction and mode coupling

Abstract

In typical applications of modeling underwater sound propagation, three-dimensional effects are assumed to be relatively weak and two-dimensional models are applied on a vertical plane to predict acoustic signals. However, this assumption breaks down for many shallow-water environments. For example, evidence of horizontal refraction has been documented in the context of nonlinear internal waves and sloping bathymetry. In this work, three-dimensional effects are modeled using a coupled-mode technique which includes the effects of out-of-plane scattering. Several examples of propagation in three-dimensional environments will be presented. A decomposition of the field into modal amplitudes will be used to identify features in the environment responsible for the observed effects on the acoustic field. © 2012 Acoustical Society of America.