Comparisons of laboratory scale measurements of three-dimensional acoustic propagation with solutions by a parabolic equation model

Sturm, Frédéric; Korakas, Alexios

doi:10.1121/1.4770252

Cited by 25 publications

(20 citation statements)

References 33 publications

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“…[8][9][10][11][12][13][14][15] While these experiments have been useful for their intended purpose, they represent idealistic bathymetries that are not found in the ocean. The approach employed in this work is to use 1 DISTRIBUTION STATEMENT A.…”

Section: Approachmentioning

confidence: 99%

Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region

Sagers¹

2013

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The long-term scientific goal of this project is to advance understanding of three-dimensional (3D) acoustic propagation in range-dependent ocean waveguides by studying propagation in a scale-model laboratory environment. OBJECTIVESThe objective of this work is to generate high quality acoustic data, measured in the laboratory, that will (1) provide a benchmark standard for 3D numerical models currently being developed, (2) allow researchers to carefully investigate 3D acoustic propagation in a controlled waveguide, and (3) assist ONR in planning for future experiments in ocean environments with slopes and canyons. APPROACHThe development of fully 3D numerical acoustic propagation models is an area of ongoing research. [1][2][3][4][5][6][7] These models have the potential to be very accurate, but comparisons between data taken at sea and numerical predictions often suffer because of insufficient environmental inputs to the numerical model. This is already a problem for two-dimensional (2D) data-model comparisons and is likely to be a perpetual problem when trying to employ 3D numerical models to describe experimental data.An alternative way to provide benchmark-quality data for numerical models is to conduct physical scale-model laboratory experiments. Scale-model experiments permit tight control over many of the variables affecting acoustic propagation, such as water temperature, bathymetry, source/receiver geometry, surface and seafloor roughness, and the geoacoustic properties of the modeled seafloor. Control over these variables allow for precise observation of 3D acoustic propagation effects such as horizontal refraction, shadow zones, multiple mode arrivals, and intra-mode interference.Much of the prior work in scale-model experiments has employed flat or sloping bottoms or random rough surfaces. [8][9][10][11][12][13][14][15] While these experiments have been useful for their intended purpose, they represent idealistic bathymetries that are not found in the ocean. The approach employed in this work is to use 1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

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Section: Approachmentioning

confidence: 99%

Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region

Sagers¹

2013

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“…rays that propagate up-slope before connecting a source to a receiver. 15,17 The issue of cross-slope wedge propagation has been discussed in detail in 9,18,19 for experimental data and for analytical predictions of adiabatic and non-adiabatic propagation using the parabolic equation model 3DWAPE; 17 the model was able to provide extremely accurate predictions in all cases. The main goal of the work presented here is to develop a benchmarking of cross-slope wedge propagation with three-dimensional models, relying on normal mode and ray tracing theory; the analytical cases and the experimental data for which 3DWAPE was already benchmarked are again considered.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental data for benchmarking was obtained from a scale experiment, that was developed in July 2007 at the LMA-CNRS laboratory in Marseille, using an indoor shallow water tank with dimensions 10-m long, 3-m wide and 1-m deep., 18 A bottom sloped half-space was made with river sand, whose properties were measured carefully. Five-cycle pulses with Gaussian envelopes were transmitted in the watercolumn overlying the sandy bottom for three different depths of the acoustic source.…”

Section: Experimental Datamentioning

confidence: 99%

Three-dimensional model benchmarking for cross-slope wedge propagation

Rodríguez

Sturm

Petrov

et al. 2017

Proceedings of Meetings on Acoustics

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“…[37]) and Sturm and Korakas (Ref. [38]) who applied a PE method to treat acoustical propagation in a slopingbottom environment, and observed by Korakas et al (Ref. [39]) and Sturm and Korakas (Ref.…”

mentioning

confidence: 99%

“…[39]) and Sturm and Korakas (Ref. [38]) in a model experiment for cross-slope propagation. The third effect was also treated by Jensen and Tindle (Ref.…”

mentioning

confidence: 99%

Generalized ray method for three-dimensional propagation in a penetrable wedge

2018

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A generalized ray solution is presented for the three-dimensional (3-D) acoustic field produced by a transient point source in a rigid-bottom, fast-speed fluid-bottom, and fast-speed elastic-bottom wedge modeling a continental shelf environment. The effect of diffraction (scattering) at the wedge apex is ignored in the solution, but nevertheless the solution is exact and complete for the image component of the field, expressed by a sum of partial waves including a pulse emitted from the source plus a finite number of pulses reflected off the wedge boundaries. Time records of the acoustic pressure illustrating 3-D acoustical propagation effects are evaluated at five receivers located at equal radial range in the horizontal from the source, but different orientation to the source, measured by the azimuthal angle assuming values: 0 • (down-slope), 45 • (obliquely down-slope), 90 • (cross-slope), 135 • (obliquely up-slope), and 180 • (up-slope). The arrival times of the spherical and head waves propagating along various paths are evaluated at each receiver for each bottom. It was found that the time interval between the first arrival and the ultimate arrival diminished, and the pulses became more peaked, as the azimuthal angle of the receiver increased. For the rigid-bottom wedge, we have found that all backscattered pulses are significant at the up-slope receiver. For the fluid-bottom wedge, we have found that: at each receiver, the source-pulse is preceded by the ground wave which is much weaker than the water wave; and, at the up-slope receiver, the backscattered pulses are insignificant. For the elastic-bottom wedge, we have found that: at each receiver, the ground-wave-response begins earlier than that in the fluid-bottom wedge, and thus the record separates out into distinct ground-wave and water-wave phases; and, at the up-slope receiver, the backscattered pulses are significant.

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Comparisons of laboratory scale measurements of three-dimensional acoustic propagation with solutions by a parabolic equation model

Cited by 25 publications

References 33 publications

Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region

Three-Dimensional Scale-Model Tank Experiment of the Hudson Canyon Region

Three-dimensional model benchmarking for cross-slope wedge propagation

Generalized ray method for three-dimensional propagation in a penetrable wedge

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