Non-parabolic Marching Algorithm for Sound Field Calculations in the Inhomogeneous Ocean Waveguide.

摘要

LONG-TERM GOALS. The long-term purpose is to develop a new effective algorithm for sound field calculations in the inhomogeneous ocean waveguide. This algorithm will not involve parabolic approximation and can be considered as principally exact (at least for 2-D inhomogeneities of the sound speed field). Thus, it can be used in cases when the phase of the acoustic field should be calculated accurately enough. It will be able to calculate not only acoustic field but the entries of scattering matrix for the modes of the ocean waveguide as well. The case of uneven fluid bottom with losses will be also considered. Thus, the algorithm will be able to provide exact solutions of the wave equation with two-dimensional inhomogeneities both for shallow- and deep-water situations. SCIENTIFIC OBJECTIVES. To develop an algorithm effectively calculating Jost solutions (JS, see below) for the inhomogeneous waveguide in the deep water case without attenuation. To express the Green function of the wave equation and scattering matrix (S-matrix) for the ocean waveguide in terms of JS. Generalize the algorithm to the case of uneven bottom with losses (shallow water case). To incorporate into the algorithm calculation of travel times of different modes. To develop appropriate code for the acoustic field and S-matrix calculations and to check it with the help of suitable benchmark problems.