Reflection of oblique incident acoustic waves at various fluid–solid interface for varying material properties

Abstract

In this paper, the reflection of acoustic waves obliquely incident onto various fluid–solid interfaces is investigated. This study aims to measure the influence of solid material properties on the acoustic attenuation magnitude, for oblique incidence at varying frequencies. A detailed comparison is documented by plotting the reflection coefficient curve for each case, while meticulously varying the porosity & permeability of the poroelastic solid. Further attention is focused on identifying the shift in the pseudo-Brewster angle and the dip in the reflection coefficient minima for the aforementioned permutations in attenuation to measure its acoustic response. To enable this, the reflection and absorption of acoustic plane waves incident upon half-space and two-layer interfaces are modelled (by including viscous and thermal losses) and studied. Based on the findings, the study draws significant conclusions on the strong influence of the propagating media on the shape of the reflection coefficient curve and the relative influence of the permeability, porosity, and driving frequency on the pseudo-Brewster angle and the curve minima.