Effects of bottom attenuation on acoustic propagation with a modified ray theory
作者:
W. L. Siegmann,
M. J. Jacobson,
L. D. Law,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1987)
卷期:
Volume 81,
issue 6
页码: 1741-1751
ISSN:0001-4966
年代: 1987
DOI:10.1121/1.394789
出版商: Acoustical Society of America
关键词: GEOMETRICAL ACOUSTICS;ATTENUATION;DEPTH;AMPLITUDES;WAVE PROPAGATION;WATER;UNDERWATER
数据来源: AIP
摘要:
The influence on ray propagation of including both attenuation and beam displacement at the bottom of a shallow‐water isospeed channel is determined. Attenuation is incorporated using the Mackenzie‐bottom model, rather than the commonly used Rayleigh reflection theory. Properties of displacement are studied as a function of launch angle and parameters such as bottom‐to‐water density, channel depth in wavelengths, and channel aspect ratio. Differences in beam displacement for the two bottom models are shown to affect the number and geometry of rays between surfaced source and receiver. Formulas for per‐ray amplitude and phase shift and for incoherent total‐field intensity are developed. Comparisons are made between these quantities for both modified and classical ray theory with a Mackenzie bottom, and also for both Mackenzie‐ and Rayleigh‐bottom models using modified rays. Numerical computations show significant phase and amplitude differences arising in both types of comparisons.
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