Time Autocorrelation of Sonic Pulses Propagated in a Random Medium

Campanella, S. J.; Favret, Andrew G.

doi:10.1121/1.1911845

Cited by 6 publications

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“…8,9 Laboratory experiments have perturbed the sound speed using thermistors or acoustic lenses in tanks with a homogeneous fluid (e.g., Refs. [10][11][12][13][14], but those experiments did not have a depth-varying sound speed profile as in the oceans.…”

Section: Introductionmentioning

confidence: 99%

Sound propagation in a continuously stratified laboratory ocean model

Zhang

Swinney

2017

The Journal of the Acoustical Society of America

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The propagation of sound in a density-stratified fluid is examined in an experiment with a tank of salty water whose density increases continuously from the fluid surface to the tank bottom. Measurements of the height dependence of the fluid density are used to calculate the height dependence of the fluid salinity and sound speed. The height-dependent sound speed is then used to calculate the refraction of sound rays. Sound propagation in the fluid is measured in three dimensions and compared with the ray analysis. This study provides a basis for laboratory modeling of underwater sound propagation in the fluctuating stratified oceans.

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Section: Introductionmentioning

confidence: 99%

Sound propagation in a continuously stratified laboratory ocean model

Zhang

Swinney

2017

The Journal of the Acoustical Society of America

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“…For instance, heating thermistors were used to generate thermal turbulence while an acoustic signal propagated through the perturbed medium (air or water). They provided very interesting results in terms of intensity moment [2], amplitude fluctuations [9,34] or spatial [33] and time correlation [6]. However, they are not fully reproducible since they only allow to recover the statistical behavior of the induced fluctuations.…”

Section: Introductionmentioning

confidence: 99%

An Ultrasonic Testbench for Emulating the Degradation of Sonar Performance in Fluctuating Media

Real

Habault

Cristol³

et al. 2017

Acta Acustica united with Acustica

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A scaled experimental protocol, in a water tank, is proposed to mimic the effects of medium heterogeneities on underwater acoustic propagation. The procedure consists in transmitting an ultrasonic wave (f = 2.25 MHz) through a RAndom Faced Acoustic Lens (RAFAL) in order to induce a spatially fluctuating sound pressure field. A scaling process based on a dimensional analysis ensures the representativeness of the experiment, when compared to the fluctuations of a few kHz continuous waves in the ocean. The regimes of saturation and unsaturation are explored by tuning the statistical parameters of the RAFAL's output face, the signal frequency and the propagation distance in the water tank. The control and reproducibility of the measurements is therefore ensured. The influence of volume effects is especially studied, since the experiments were conducted in free field conditions. Results in terms of mutual coherence function (second-order moment) are presented ; a good agreement is found between the values of radii of coherence calculated using experimental and simulation data, as well as theoretical results. The evaluation of the complex pressure distribution highlights the relevance of the experimental scheme, since behaviors typical of the regimes of fluctuations (saturation and unsaturation) are found.

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Physical Modeling of Underwater Acoustics

Zomig¹

1979

Topics in Current Physics

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With 17 FiguresIn the attempt to explain underwater acoustic phenomena and to exploit these phenomena in useful ways a number of techniques for analysis have been developed. These include, but are not limited to, mathematical analysis, numerical modeling, in situ empirical description, and physical modeling. All have made substantial contributions to our understanding of the WQy in which sound behaves in water. The purpose of this chapter is to review the methods and results of physical modeling and to discuss its role in underwater acoustic research. To do this an attempt will be made to define the technique and to set in perspective its rel~tionship to the other methods of analysis. Some attention will be paid to the use of small natural bodies of water, lakes and bays, for example, as model facilities. However, the main thrust of the discussion will be concerned with artificially constructed model tanks and particularly with the study of surface scattering in such facilities. Physical model research has been conducted for some time in a number of contexts. Unfortunately, until the present there has been little communication among various investigators on matters of technique. By discussing the development of physical model experimental methods and illustrating the degree of precision and flexibility possible in model tanks this chapter seeks to encourage and facilitate a more widespread and systematic employment of physical modeling in future underwater acoustic research. Background Information Definition and PurposePhysical modeling in this context refers to the empirical investigation of underwater acoustic phenomena in physical situations other than the ocean. This somewhat imprecise definition is intended to include acoustic experimentation in water tanks, lakes, bays and so forth; physical environments which, by virtue of their stability, convenience and flexibility, provide the experimenter with opportunities for precision, repeatability, and economy not normally available in ocean experimentation. Physical modeling is, in general, useful for two broad classes of application. The first, and probably more significant of these roles is in the validation of analyt-J. A. DeSanto (ed.), Ocean Acoustics

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Time Autocorrelation of Sonic Pulses Propagated in a Random Medium

Cited by 6 publications

References 0 publications

Sound propagation in a continuously stratified laboratory ocean model

Sound propagation in a continuously stratified laboratory ocean model

An Ultrasonic Testbench for Emulating the Degradation of Sonar Performance in Fluctuating Media

Physical Modeling of Underwater Acoustics

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