Three-Dimensional Coupled Normal Mode Model for Sound Propagation in Shallow Water with Irregular Bottom Bathymetry.

摘要

A three-dimensional (3D) coupled normal mode model for studying sound propagation in a complex coastal environment is developed. This development corresponds to a significant upgrade of earlier version of the model in which a flat, rigid bottom was used. By imposing the general boundary conditions for an irregular, non- rigid bottom, the coupling coefficient integrals in the system of differential equations governing the mode amplitude are reformulated The model upgrade entails a numerical implementation of the revised formulae. With the improved physics, this latest version is capable of modeling the 3D acoustic wave-field in shallow water where sound speed, water depth and sediment properties can vary with horizontal location. To demonstrate this enhanced capability, the model is used here to simulate the interactions of the normal modes as they propagate up a sloping bottom.