Acoustic Propagation in a Channel with Range‐Dependent Sound Speed
作者:
J. T. Warfield,
M. J. Jacobson,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1969)
卷期:
Volume 45,
issue 5
页码: 1145-1156
ISSN:0001-4966
年代: 1969
DOI:10.1121/1.1911585
出版商: Acoustical Society of America
数据来源: AIP
摘要:
Ray geometry, travel time, and spreading loss are studied in a horizontal channel in which sound speed depends on range. Formulas valid for a general sound‐speed function are developed, and then specialized to the class of linear functions. Rays reaching a fixed receiving point are then isolated and studied. Properties of corresponding arrivals at a fixed receiving point are compared for the cases of a range gradient channel and a constant sound speed channel. Differences in initial inclination angle, travel time, and spreading loss are found and bounds on these differences are obtained. For a CW source, the total field at a receiving point is then determined. It is demonstrated that the introduction of even a weak range gradient causes major changes in the amplitude and phase, including the occurrence of interference nulls accompanied by a sharp offset in phase. Finally, approximate formulas are developed for the phase shift of the total field, caused by a constant range gradient, relative to the phase in isospeed channels.
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