A comparison of the reflection coefficient predictions of two competing sediment acoustic models

Abstract

Currently, there are several competing models that have been used to describe the acoustic properties of sandy sediments. These models include those that assume the sediment to behave as an acoustic fluid, a viscoelastic solid, and as a porous media following Biot theory. Perhaps the two most sophisticated acoustic models that have been applied to sand are the Viscous Grain Shearing (VGS) model of Buckingham and the Extended Biot (EB) model of Chotiros. While both of these models have been found to agree with measured sound speed dispersion and attenuation data, previous work has shown that the reflection coefficients predicted using these models disagree. In this work, the reflection coefficient predictions of the VGS and EB models will be compared for both the case of a homogeneous sand half-space and the case of a sand layer overlying a rock substrate. [Work supported by ONR, Ocean Acoustics.]