On the Application of Asymptotic Formulae Based on the Modified Maslov Canonical Operator to the Modeling of Acoustic Pulses Propagation in Three-Dimensional Shallow-Water Waveguides

Resumo

In this study a technique for the modeling of propagation of acoustic pulses in shallow-water waveguides with three-dimensional bottom inhomogeneities is described. The described approach is based on the ray theory of sound propagation and the method of modified Maslov canonical operator. Representation of acoustical field in terms of the canonical operator gives several important advantages in practical computations. In particular, it is possible to compute the time series of a pulse at a reception point located on the caustics of a family of rays. Besides, a significant part of calculations within the proposed approach can be performed analytically; therefore, overall computational costs are substantially reduced. As an example, sound propagation in a wedge-shaped waveguide representing a shelf area near the coast line is considered. The ray geometry in such a waveguide is discussed both in the isovelocity case and in the presence of the thermocline in the water column. For both cases, the time series of an acoustical pulse propagating along the track aligned along the isobaths (parallel to the apex edge of the wedge) is calculated.