Sound propagation in shallow water with surface waves

Abstract

Wavefront modeling can be used to calculate acoustic pulse propagation in shallow water with real surface waves. The method uses ray tracing but phase and amplitude are found from approximations to a phase integral. The lowest order approximation is the conventional geometric ray. Higher order approximations describe caustics, shadow zones and focusing. Reflection from sloping curved boundaries also leads to a range dependent horizontal wave number and requires modification of the phase integral and phase derivatives. Results are in good agreement with an experiment in which 10-kHz short pulses were transmitted in shallow water with 0.8-m peak-to-trough surface waves and a sloping bottom. [Work supported by ONR.]