Wavefront modelling of pulse propagation

Abstract

Wavefront modelling has been developed for the rapid calculation of receiver waveforms in underwater sound pulse propagation. The method uses a solution of the wave equation which expresses the field as a sum over phase integrals. Each phase integral corresponds to a particular sequence of reflections or turning points and is evaluated analytically by using stationary phase approximations. Each point of stationary phase corresponds to a ray path. Pairs or triplets of stationary phase points correspond to caustics or foci and the phase and amplitude of the field is found directly. The method can handle rapid range dependence such as occurs with surface waves in shallow water and double scattering from the same surface. The method is fast and accurate and examples will be discussed. [Work supported by ONR.]