SPECIAL ISSUE — COMPUTATIONAL METHODS IN UNDERWATER ACOUSTICSNo Access

A METHOD FOR THE TREATMENT OF A SLOPING SEA BOTTOM IN THE PARABOLIC APPROXIMATION

J. S. PAPADAKIS

Institute of Applied and Computational Mathematics F.O.R.T.H., P.O. Box 1527, Heraklion 711 10, Crete, Greece

also Dept. of Mathematics, University of Crete.

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and

B. PELLONI

Institute of Applied and Computational Mathematics F.O.R.T.H., P.O. Box 1527, Heraklion 711 10, Crete, Greece

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https://doi.org/10.1142/S0218396X96000234Cited by:6 (Source: Crossref)

Abstract

The impedance boundary condition for the parabolic approximation is derived in the case of a sea bottom profile sloping at a constant angle, as a non-local boundary condition imposed exactly at the interface. This condition is integrated into the IFD code for the numerical computation of the pressure field and implemented to test its accuracy in some benchmark cases, for which the backscattered field is negligible.

It is shown that by avoiding the sloping interface, the results obtained are closer to the benchmark results given by normal mode codes solving the full Helmholtz equation, such as the 2-way COUPLE code, than those of the standard IFD or other 1-way codes, at least for problems that do not have significant backscattering effects.