Modeling the Lower Bound for a Marine Acoustic Waveguide with Elastic Bottom

Abstract

At the present time, theory of sound propagation in a sea is based on the theory of non-ideal waveguides. In particular, plane-layered waveguide models are used as the basis for computer simulation of sound fields in inhomogeneous waveguides, where the unconsolidated sedimentary layer is of greatest interest. A characteristic feature of this layer is the presence of inhomogeneity in the physical properties and geometry of bottom, which cause local acoustic field perturbations. In the case when parameters of the waveguide are weakly dependent on distance, the use of plane-layered models proved to be fruitful. Such models are taking into account the geoacoustic properties of the bottom and the velocity profile of sound. The paper is devoted to the modelling lower bound of a waveguide with elastic bottom. It should be noted that solution for classical Pekeris waveguide contains branch line integrals, which to not allow us the method of particular domains to modelling waveguides with more complex structure of bottom. Thus we will consider a waveguide on a rigid basement, where sufficiently large elastic bottom layer with attenuation will adequately describe bottom properties. The solution for such waveguide does not presented in literature and may be a basis for modelling sound propagation in the waveguides with stepped elastic bottom.