Broadband modeling of sound propagation in shallow water with an elastic bottom

Abstract

Broadband sound propagation in shallow water is studied in this work. It is essential for a shallow water sound propagation model to involve the effects of bottom interaction and range-dependence. Therefore, a realistic model that consists of a fluid overlying an elastic sloping bottom is treated in this paper, where the effects of shear waves are included. An approach to calculate the vector sound field is presented. The range-dependent seismo-acoustics problem in the frequency-domain is solved by the parabolic approximation method, and the Fourier synthesis technique of the frequency-domain solutions is implemented to model the received time series of a broadband sound propagation. Due to the elastic boundary conditions, the Scholte waves that travel along the ocean bottom are generated. Dispersion characteristics of the normal modes and the Scholte waves are exhibited by multiple mode arrivals during the propagation. The dispersion curves of normal modes and the Scholte waves are demonstrated for the considered case. Energy conversion between normal modes and the Scholte waves due to the sloping bottom is analyzed. The characteristics of the Scholte waves are studied.