Stochastic simulation and first‐order multiple scatter solutions for acoustic propagation through oceanic internal waves
作者:
Bruce J. Bates,
Susan M. Bates,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1987)
卷期:
Volume 82,
issue 6
页码: 2042-2050
ISSN:0001-4966
年代: 1987
DOI:10.1121/1.395648
出版商: Acoustical Society of America
关键词: WAVE PROPAGATION;MULTIPLE SCATTERING;SEAS;INTERNAL WAVES;COMPUTERIZED SIMULATION;SOUND WAVES;SOUND VELOCITY
数据来源: AIP
摘要:
The existing theory of acoustic propagation through an oceanic internal wave field with a Garrett and Munk spectrum is modified and, by numerical computation, is shown to be consistent. The fractional sound speed computation is rederived to satisfy the Garrett and Munk spectrum and used to compute a stochastic simulation of the internal wave sound speed fluctuation field. The Garrett and Munk spectrum in (ω,j) space has been normalized by 4π, and the acoustic scattering is redefined to accommodate scattering from the internal wave phase fronts as in an acoustic phase grating. These modifications are then used to compute the coherent acoustic intensity by two methods: a first‐order multiple scatter approximation and a stochastic simulation. Also, the Rytov approximation is shown to be equivalent to the first‐order multiple scatter approximation in the form of the stochastic parabolic equation method in the unsaturated region. The computational results show agreement in the weak scattering region using typical deep ocean values. The stochastic simulation method is accurate in the saturated and unsaturated regions; however, the method requires long computer execution times. Phase front fragments propagating along rays with sound speeds reduced by the stochastic internal wave field are used to discuss the computational results.
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