Underwater noise emissions from bubble clouds

Lu, N.; Prosperetti, Andréa; Yoon, Suk Wang

doi:10.1109/48.103521

Cited by 79 publications

(39 citation statements)

References 17 publications

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“…Plot showing the observed peak frequency f 0 b of the pressure spectrum from breaking waves and the predicted resonant frequency fR for a cylindrical bubble cloud computed using the method described by Lu et al (1990) [Loewen & Melville, 1992]. A plot showing that the acoustic energy radiated by a breaking event Ea is proportional to the dissipated mechanical wave energy EL.…”

Section: Spectral Dissipation Estimatesmentioning

confidence: 99%

“…In particular, they showed that their method successfully predicted the frequency of the resonant oscillations of a cylindrical bubble column generated in the laboratory (Yoon, Crum, Prosperetti & Lu, 1991 fR (Hz) Figure 1.6. Plot showing the observed peak frequency f 0 b of the pressure spectrum from breaking waves and the predicted resonant frequency fR for a cylindrical bubble cloud computed using the method described by Lu et al (1990). [Loewen & Melville, 1992].…”

Section: Chapter1mentioning

confidence: 99%

“…where r 0 is the radius of the bubble cloud, r= 1 is the ratio of specific heats under A more general theory for sound generation by collective oscillations of bubble clouds was proposed by Prosperetti (1988) and Lu, Prosperetti & Yoon (1990). Lu et al (1990) outlined their approach and used it to predict the resonant collective oscillation frequencies of bubbly regions of various geometries.…”

Section: Chapter1mentioning

confidence: 99%

“…Lu et al (1990) outlined their approach and used it to predict the resonant collective oscillation frequencies of bubbly regions of various geometries. In particular, they showed that their method successfully predicted the frequency of the resonant oscillations of a cylindrical bubble column generated in the laboratory (Yoon, Crum, Prosperetti & Lu, 1991 fR (Hz) Figure 1.6.…”

Section: Chapter1mentioning

confidence: 99%

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Ambient noise and surface wave dissipation in the ocean

Felizardo¹

1993

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Section: Spectral Dissipation Estimatesmentioning

confidence: 99%

Section: Chapter1mentioning

confidence: 99%

Section: Chapter1mentioning

confidence: 99%

Section: Chapter1mentioning

confidence: 99%

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Ambient noise and surface wave dissipation in the ocean

Felizardo¹

1993

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“…The measured acoustic spectra showed low frequency peaks from 260 to 550 Hz. Lu et al (1990) used averaged equations based on the assumption that the bubbly cloud is a continuum described by effective bulk properties to calculate the modes of oscillation of cylindrical bubble clouds. Yoon et al (1991) compared the observed frequencies to theoretically predicted values using the results ofLu et al (1990).…”

Section: Lj Measurements 2f ~ Sound Generated Hi Breakinand Wavesmentioning

confidence: 99%

Laboratory measurements of the sound generated by breaking waves

Loewen¹

1991

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in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Oceanographic EngineeringBreaking waves dissipate energy, transfer momentum from the wind to surface currents and breaking enhances the transfer of gas and mass across the air-sea interface. Breaking waves are believed to be the dominant source of sea surface sound at frequencies greater than 500 Hz and the presence of breaking waves on the ocean surface has been shown to enhance the scattering of microwave radiation. Previous studies have shown that breaking waves can be detected by measuring the microwave backscatter and acoustic radiation from breaking waves. However, these techniques have not yet proven effective for studying the dynamics of breaking. The primary motivation for the research presented in this thesis was to determine whether measurements of the sound generated by breaking waves could be used to quantitatively study the dynamics of the breaking process.Laboratory measurements of the microwave backscatter and acoustic radiation from two-dimensional breaking waves are described in Chapter 2. The major findings of this Chapter are: 1) the mean square acoustic pressure and backscattered microwave power correlate with the wave slope and dissipation for waves of moderate slope, 2) the mean square acoustic pressure and backscattered microwave power correlate strongly with each other, and 3) the amount of acoustic energy radiated by an individual breaking event scaled with the amount of mechanical energy dissipated by breaking. The observed correlations with the mean square acoustic pressure are only relevant for frequencies greater than 2200 Hz because lower frequencies were below the first acoustic cut-off frequency of the wave channel.In order to study the lower frequency sound generated by breaking waves another series of two-dimensional breaking experiments was conducted. Sound at frequencies as low as 20 Hz was observed and the mean square acoustic pressure in the frequency band from 20 Hz-l kHz correlated strongly with the wave slope and dissipation. A characteristic low frequency signal was observed immediately following the impact of the plunging wave crest. The origin of this low frequency signal was found to be the pulsating cylinders of air which are entrained by the plunging waves. The pulsation frequency correlated with both the wave slope and dissipation. Following the characteristic constant frequency signal, approximately 0.25 s after the initial impact of 2 the plunging crest, another low frequency signal was typically observed. These signals were generally lower in frequency initially and then increased in frequency as time progressed.To determine if three-dimensional effects were important in the sound generation process and to measure the sound beneath larger breaking waves a series of experiments was conducted in a large multi-paddle wave basin. Three-dimensional breaking waves were generated and the sound produced by breaking was measured in the frequency range from 10 Hz to 20 kHz. 'The observed...

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Ocean bottom pressure records from the Cascadia array and short surface gravity waves

Peureux

Ardhuin

2016

JGR Oceans

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The ocean bottom pressure records from eight stations of the Cascadia array are used to investigate the properties of short surface gravity waves with frequencies ranging from 0.2 to 5 Hz. It is found that the pressure spectrum at all sites is a well‐defined function of the wind speed U10 and frequency f, with only a minor shift of a few dB from one site to another that can be attributed to variations in bottom properties. This observation can be combined with the theoretical prediction that the ocean bottom pressure spectrum is proportional to the surface gravity wave spectrum E(f) squared, times the overlap integral I(f) which is given by the directional wave spectrum at each frequency. This combination, using E(f) estimated from modeled spectra or parametric spectra, yields an overlap integral I(f) that is a function of the local wave age f/fPM=fU10/0.13 g. This function is maximum for f∕fPM = 8 and decreases by 10 dB for f∕fPM = 2 and f∕fPM = 30. This shape of I(f) can be interpreted as a maximum width of the directional wave spectrum at f∕fPM = 8, possibly equivalent to an isotropic directional spectrum, and a narrower directional distribution toward both the dominant low frequencies and the higher capillary‐gravity wave frequencies.

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Underwater noise emissions from bubble clouds

Cited by 79 publications

References 17 publications

Ambient noise and surface wave dissipation in the ocean

Ambient noise and surface wave dissipation in the ocean

Laboratory measurements of the sound generated by breaking waves

Ocean bottom pressure records from the Cascadia array and short surface gravity waves

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