Accession Number:

AD1113295

Title:

An Approximate Form of the Rayleigh Reflection Loss and its Phase: Application to Reverberation Calculation

Descriptive Note:

Journal Article - Embargoed Full-Text

Corporate Author:

NATO UNDERSEA RESEARCH CENTRE LA SPEZIA (ITALY) LA SPEZIA United States

Personal Author(s):

Report Date:

2012-04-01

Pagination or Media Count:

8.0

Abstract:

A useful approximation to the Rayleigh reflection coefficient for two half-spaces composed of water oversediment is derived. This exhibits dependence on angle that may deviate considerably from linear in the intervalbetween grazing and critical. It shows that the non-linearity can be expressed as a separate function that multipliesthe linear loss coefficient. This non-linearity term depends only on sediment density and does not depend onsediment sound speed or volume absorption. The non-linearity term tends to unity, i.e., the reflection lossbecomes effectively linear, when the density ratio is about 1.27. The reflection phase in the same approximationleads to the well-known effective depth and lateral shift. A class of closed-form reverberation and signal-toreverberationexpressions has already been developed C. H. Harrison, J. Acoust. Soc. Am. 114, 274427562003 C. H. Harrison, J. Comput. Acoust. 13, 317340 2005 C. H. Harrison, IEEE J. Ocean. Eng. 30, 6606752005. The findings of this paper enable one to convert these reverberation expressions from simple linear loss tomore general reflecting environments. Correction curves are calculated in terms of sediment density. These curvesare applied to a test case taken from a recent ONR-funded Reverberation Workshop.

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE