Non-Local Boundary Conditions for High-Order PE Models with Application to Scattering from a Rough Surface

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Authors
  1. Brooke, G.H.
  2. Thomson, D.J.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
Numerical PE (parabolic equation) solvers for underwater sound propagation usually approximate the subbottom radiation condition by appending an absorbing layer to the computational mesh. An alternative procedure uses a non-local boundary condition (NLBC) applied along (or below) the sea-bottom interface that exactly transforms the semi-infinite PE configuration into an equivalent bounded domain. In this paper, we analyze NLBC's that are expressed in terms of plane-wave reflection coefficients and describe their implementation in the context of higher-order Pade-based PE algorithms. In particular, we develop non-local boundary conditions to account for the coherent losses due to scattering by a statistically-rough sea surface. Several numerical examples are presented to illustrate the numerical implementation of NLBC's for higher-order PE's.
Keywords
Radiation condition;Absorbing layer;Non-local boundary condiction (NLBC);Plane waves;Reflection coefficients;Pade approximants;Coherent losses;Numerical implementation
Report Number
DREA-TM-1999-121 — Technical Memorandum
Date of publication
01 Aug 1999
Number of Pages
36
DSTKIM No
99-01723
CANDIS No
511742
Format(s):
Hardcopy;Document Image stored on Optical Disk

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