Multifilament source model for short-range underwater acoustic problems involving penetrable ocean bottoms

Accurate numerical solutions generated with a new computational model are presented for several range-dependent underwater acoustic problems involving penetrable ocean bottoms. The multifilament source model [Boag et al., ‘‘Analysis of acoustic scattering from fluid cylinders using a multifilament source model,’’ J. Acoust. Soc. Am. 83, 1–8 (1988)], originally developed to treat acoustic scattering by arbitrarily shaped cylinders embedded in an infinite medium, has been extended to solve short-range ocean acoustic problems. Source model solutions for two different range-dependent problems agree with solutions that were obtained with Evans’ COUPLE model [R. B. Evans, ‘‘A coupled mode solution for acoustic propagation in a waveguide with stepwise depth variations of a penetrable bottom,’’ J. Acoust. Soc. Am. 74, 188–195 (1983)]. These comparisons demonstrate the source model’s ability to describe propagation in a shallow water environment with rapidly varying bathymetry and a lossy, penetrable bottom.