A Study Of Pulse Scattering In A Waveguide

Abstract

Abstract : The problem of the scattering of a continuous acoustic wave(CW)from a submerged object in a waveguide has received extensive treatment in the frequency domain, where phenomena associated with the resonant behavior of the object have been studied in detail. This paper concentrates on the time-domain interpretation of the scattering problem. Computation of the scattered field from an incident pulse, which requires calculations for many frequencies, is performed using a new perturbation technique (computed to all orders that allows rapid calculation of the waveguide modes. An implementation of the inverse Fourier transform is presented that is more appropriate to resonance-type spectra. The computational tools developed are used to elucidate various physical aspects of pulse scattering in a waveguide, including: group velocity behavior, direct modal contributions, and resonance contributions from individually excited modes. Acoustic scattering, shallow water, waveguide propagation.