Extension of the Method of Normal Modes to Sound Propagation in an Almost-Stratified Medium

Pierce, Allan D.

doi:10.1121/1.1909303

Cited by 199 publications

(84 citation statements)

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“…For the latitudes of interest in this analysis, this sampling results in range intervals of about 7 km. In the APL model, the environmental profiles are determined through an environmental partitioning process that determines regions of constant environment on a spatial scale that is considered appropriate for an adiabatic-normal-mode propagation model [8,9,10]. These partitions, which are strongly dependent on the spatial variability in the bathymetry, can result in very fine range grids in continental shelf and slope regions and much coarser resolution in the deep-water abyssal plains (e.g., range intervals from 5 km to over a 100 km).…”

Section: Analysis Methodologymentioning

confidence: 99%

Ship-Induced Noise Predictions in the Atlantic and the Pacific: A Comparison of Two Noise Models

Heitmeyer¹,

Wales²,

Pflug³

et al. 2006

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Section: Analysis Methodologymentioning

confidence: 99%

Ship-Induced Noise Predictions in the Atlantic and the Pacific: A Comparison of Two Noise Models

Heitmeyer¹,

Wales²,

Pflug³

et al. 2006

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“…This approximation, also called the adiabatic approximation was originally introduced for cylindrically symmetric range dependent waveguides by Pierce [35], and more formal derivations were obtained in [36]. Using Eq.…”

Section: Normal Modes For Range Dependent Environmentsmentioning

confidence: 99%

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Shmelev¹

2011

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This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental slopes. A simple idealized model of the ocean waveguide is used to analytically study the properties of acoustic normal modes and their perturbations due to waves of each type. The combined approach of a semi-quantitative study based on the geometrical acoustics approximation and on fully three-dimensional coupled mode numerical modeling is used to examine the azimuthal dependence of sound wave horizontal reflection from, transmission through and ducting between straight parallel waves of each type. The impact of the natural crossings of nonlinear internal waves on horizontally ducted sound energy is studied theoretically and modeled numerically using a three-dimensional parabolic equation acoustic propagation code. A realistic sea surface elevation is synthesized from the directional spectrum of long swells and used for three-dimensional numerical modeling of acoustic propagation. As a result, considerable normal mode amplitude scintillations were observed and shown to be strongly dependent on horizontal azimuth, range and mode number. Full field numerical modeling of low frequency sound propagation through large sand waves located on a sloped bottom was performed using the high resolution bathymetry of the mouth of San Francisco Bay. Very strong acoustic ducting is shown to steer acoustic energy beams along the sand wave's curved crests.

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“…Thus the "adiabatic approximation" method was introduced, which simplifies the above coupled-mode problem by ignoring ( 1) the backscattered component of the field and (2) coupling between different-order modes at the segment interfaces. This approximation was originally introduced by Pierce [21] based on analogous results for the Schrodinger equation. The derivation here follows sections of the textbook by Jensen et al [20].…”

Section: Adiabatic Approximationmentioning

confidence: 99%

Amplitude fluctuation effects in shallow water acoustic scattering by internal waves

Fu¹

1995

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Extension of the Method of Normal Modes to Sound Propagation in an Almost-Stratified Medium

Cited by 199 publications

References 0 publications

Ship-Induced Noise Predictions in the Atlantic and the Pacific: A Comparison of Two Noise Models

Ship-Induced Noise Predictions in the Atlantic and the Pacific: A Comparison of Two Noise Models

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Amplitude fluctuation effects in shallow water acoustic scattering by internal waves

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