SPLIT-STEP FOURIER APPROXIMATIONS FOR PARABOLIC EQUATIONS

Authors
  1. Yevick, D.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN);Queen's Univ, Kingston ONT (CAN) Dept of Electrical Engineering
Abstract
The report covers the period 1 May 1993 - 30 April 1994, during which several new rapid and accurate methods for simulating acoustic wave propagation in a leaky surface duct were developed. The project was motivated by the discovery that the wide-angle split-step approximation to the one-way Helmholtz propagation operator yields anomalous results when applied to certain leaky surface duct problem. In particular, the acoustic transmission losses at ranges for which the ducted field interferes with the field which incorrectly described by this widely-employed technique. Later it was found that the error could be eliminated by setting the single free parameter in the propagator, namely the reference sound speed, to a special value. The known magnitude of this quantity was, however, completely unrepresentative of the typical sound speeds in the waveguide. At the same time, other standard parabolic equation solvers including the simplest parabolic approximation were found to yield acceptable results which are highly insensitive to the value chosen for the reference sound speed. The anomalous behavior of the wide-angle split-step propagator was quite unexpected since the approximation had been found to be more accuracte than the standard parabolic approximation in other acoustics applications.
Report Number
DREP-CRS-94-60 — Contractors Report Series
Date of publication
01 Apr 1994
Number of Pages
22
DSTKIM No
94-03586
CANDIS No
143086
Format(s):
Hardcopy;Originator's fiche received by DSIS

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