ASA 124th Meeting New Orleans 1992 October

1pUW7. A fast perturbation approach for calculating pulses in a waveguide with applications.

M. F. Werby

M. K. Broadhead

NRL, Theor. Acoust. Code 221, Stennis Space Center, MS 39529

A fast normal mode code based on a full perturbation method and a fast Fourier transform method has been developed. This enabled one to perform broadband pulse calculations to high frequencies. Further the pulse returns can be decomposed into their constituent modes. Studies are preformed on pulse returns for realistic shallow water waveguides for signals out to 25 km, the various dispersion effects are illustrated, and model arrivals are separated with increasing distance from the source. Particular emphasis is placed on strong channeling.