The Study of Sound Backscattering From Microinhomogeneities in Sea Water

Akulichev, V. A.; Bulanov, V. A.

doi:10.1007/978-1-4613-1871-2_11

Cited by 9 publications

(7 citation statements)

References 5 publications

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“…The observed growth of tensile strength to 8 bars with lowering the temperature can well be agreed with the thermal activation theory for the rate of inception of gas bubbles in the stretched liquid [1]. According to the first estimates [2], the thermal activation mechanism of bubble inception in liquid 4 He should be succeeded by the quantum mechanism associated with the underbarrier tunneling of nuclei at about 310 mK. The tensile strength should become temperature-independent and reach about 15 bar.…”

supporting

confidence: 79%

“…For radii R 0 ≫ R * , the crossover temperature proves to approximately the same as it follows from the dissipationless cavitation model [2,6]…”

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 55%

“…Therefore, in region T 2 < T ≪ T q the cavitation rate should follow log[Γ(T )/Γ(0)] ∼ T 2 . Unlike normal 3 He, the normal component density in superfluid 4 He vanishes rapidly with approaching zero temperature and the quantum cavitation is governed mainly by the well-known dissipationless term associated with the kinetic energy of a bubble in the Rayleigh-Plesset Lagrangian [2,6]. Involving the finite sound velocity correction, we find for T = 0…”

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 76%

“…This answer is a decomposition in Ṙ/u ≪ 1 if we take into account that the typical growth time of bubble is about ρuR 2 c /σ. Unlike the dissipationless kinetics [2,6], the energy dissipation of a bubble in the course of its growth results in the effective action with the kinetic terms depending explicitly on the temperature. Thus, the cavitation rate can be temperature-dependent and we can expect [23] that…”

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 99%

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Quantum nucleation of gas bubbles in liquid helium

Burmistrov,

Dubovskii

2021

Preprint

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Liquid helium under negative pressures represents a unique possibility for studying nucleation and growth dynamics of cavities at low temperatures down to absolute zero. We analyze the growth dynamics of cavities and determine the temperature behavior of quantum cavitation rate and the crossover temperature between the classical and quantum cavitation mechanisms. The energy dissipation processes, which differ in kind in normal fluid 3 He and superfluid 4 He, result in the different temperature behavior of cavitation rate in 3 He and 4 He below the thermal-quantum crossover temperature.

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supporting

confidence: 79%

“…For radii R 0 ≫ R * , the crossover temperature proves to approximately the same as it follows from the dissipationless cavitation model [2,6]…”

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 55%

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 76%

Section: The Coefficients Of Expansion Are Given Bymentioning

confidence: 99%

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Quantum nucleation of gas bubbles in liquid helium

Burmistrov,

Dubovskii

2021

Preprint

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“…Существует также еще один оригинальный метод, суть которого заключается в следующем. Резонансные газовые пузырьки имеют достаточно высокую добротность, поэтому установление стационарных колебаний пузырьков на резонансе происходит не мгновенно, а в течение некоторого времени, определяемого добротностью Q. Применяя акустические импульсы различной длительности t, по нарастанию рассеянного сигнала в зависимости от t можно определить вклад резонансных пузырьков в общее рассеяние звука различными неоднородностями [18,19].…”

unclassified

Laboratory setup for determining the influence of inhomogeneities in the water on its acoustic properties and research results

Grekov¹,

Systems²,

Grekov³

et al. 2020

MSoE

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In order to create new devices for measuring various acoustic characteristics of an aqueous medium (speed of sound, scattering and absorption coefficients), a design of a laboratory multifunctional setup has been proposed to study the effect of microinhomogeneities in water on its acoustic properties. It should be noted that the created laboratory complex is very promising for solving problems such as studying the structure of microinhomogeneities. The article provides a brief analysis of methods for measuring the scattering of ultrasound in a liquid, and also notes the results of recent studies of small-scale irregularities in the ocean and provides links to them. At the research stage, all measurements were carried out on the clouds of microbubbles , located and moving in the liquid. The technique developed by the authors allows to determine, for the mid-frequency range, the design features of primary acoustic transducers with two reflectors, one of which is acoustically semitransparent, and to make correction of the dimensions of highly stable rods made from sital or from the carbon composite, depending on obtaining the necessary spatial and temporal characteristics of the investigated acoustic field. Equations for determining the time windows are given, their values are calculated, and graphs are constructed by which it is possible to determine the volumetric section of sound scattering, without the influence of multiple reflections on the measurement results. After research at the laboratory setup, recommendations were formulated for improving the primary acoustic transducer, the ISZ-1 device, designed to measure the scattering and absorption of ultrasound in situ.

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Remote sensing of bubble clouds in sea water

Flatau

Zaneveld³

et al. 2000

Quart J Royal Meteoro Soc

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We report on the influence of submerged bubble clouds on the remote sensing properties of water. We show that the optical effect of bubbles on radiative transfer and on the estimate of the ocean color is significant. We present a global map of the volume fraction of air in water derived from daily wind speed data. This map, together with the parameterization of the microphysical properties, shows the possible significance of bubble clouds on the albedo of incoming solar energy.

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The Study of Sound Backscattering From Microinhomogeneities in Sea Water

Cited by 9 publications

References 5 publications

Quantum nucleation of gas bubbles in liquid helium

Quantum nucleation of gas bubbles in liquid helium

Laboratory setup for determining the influence of inhomogeneities in the water on its acoustic properties and research results

Remote sensing of bubble clouds in sea water

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