Theory for acoustic propagation in marine sediment containing gas bubbles which may pulsate in a non‐stationary nonlinear manner

Abstract

Whilst there is a considerable body of work in the literature on the theory of acoustic propagation in marine sediments, the incorporation of gas bubbles into such theories is done with the inclusion of assumptions which severely limit the applicability of those models to practical gas‐laden marine sediments. This paper provides a theory which does not assume that the bubble dynamics are linear, steady‐state and monochromatic. Such assumptions would be incompatible with many of the practical acoustic fields with which sediments are insonified today. These fields are necessarily high amplitude to provide adequate signal‐to‐noise ratios, given the high attenuation in gassy marine sediments; and often they utilise short pulses to obtain range resolution. This paper provides a theory appropriate for predicting the acoustically‐driven non‐stationary nonlinear dynamics of spherical gas bubbles embedded in a lossy elastic solid, and discusses how this could be incorporated into a nonlinear, time‐dependent propagation model.