Numerical simulation of acoustic propagation at a fluid-solid interface

Abstract

Propagation of acoustic pulses in the neighborhood of the interface between fluid and solid half-spaces is investigated numerically using the finite difference technique. The solid half-space may be homogeneous, or it may comprise several distinct solids of differing acoustical properties. The solid-solid interface may have arbitrary orientation with respect to the fluid-solid interface. Plots of the displacement fields clearly illustrate the wavefronts, headwaves, and surface modes near the fluid-solid interface. In the case of the inhomogeneous solid, reflection, transmission, and mode conversions at the solid-solid interface, and subsequent interactions with the fluid-solid interface give rise to a multiplicity of decay pulses. The origin and physical significance of each of these decay pulses is made evident by the displacement field pilots.