Accession Number:

AD0879641

Title:

Scattering and Reflection of Underwater Sound Waves from the Sea Surface. I. An Expression for the Scattered Field.

Descriptive Note:

Technical rept.,

Corporate Author:

SACLANT ASW RESEARCH CENTRE LA SPEZIA (ITALY)

Personal Author(s):

Report Date:

1970-12-15

Pagination or Media Count:

100.0

Abstract:

When underwater sound waves propagate from a transmitter to a receiver, part of the energy reaches the receiver after reflection from the sea surface. This boundary effect can be called the impulse response of the sea surface if the incident sound field is caused by a delta-pulse. This report uses a generalized version of the Helmholtz integral to derive an expression for the corresponding transfer function, which is a random function that depends on the frequency of the incident wave, on time, and on the source-receiver configuration. For very high frequencies the formula indicates specular reflection from each surface highlight. In the Fraunhofer domain the transfer function reduces to specular reflection with phase fluctuations. A statistical analysis mean value, frequency, time and space correlation, wave front distortion is included for that frequency domain. The perfectly flat surface is treated as a limiting case. Quantities such as effective scattering area and Fresnel zones are analysed to guide the random surface studies. Author

Subject Categories:

  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE