Frequency Dependence of Phase Speed, Group Speed, and Attenuation in Water-Saturated Sand: Laboratory Experiments

Sessarego, Jean‐Pierre; Ivakin, Anatoliy N.; Ferrand, Didier

doi:10.1109/joe.2008.927584

Cited by 27 publications

(10 citation statements)

References 22 publications

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“…Increasing energy to the A303S did not result ). Our values of S s are on par with these, despite imperfect comparison due to our higher frequency and variations in grain size distribution, which also affects S s (Sessarego et al 2008a) between studies.…”

Section: Laboratory Experimentssupporting

confidence: 45%

“…Other published values of S s are 1650 m s -1 (Knobles et al 2008), 1680 m s -1 (Hines et al 2010), 1711 m s -1 (Richardson and Briggs 1996), 1760, 1800 m s -1 (Thorsos et al 2001), and 1780 m s -1 (Hefner et al 2009). Our values of S s are on par with these, despite imperfect comparison due to our higher frequency and variations in grain size distribution, which also affects S s (Sessarego et al 2008a) between studies.…”

Section: Laboratory Experimentssupporting

confidence: 45%

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Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Wildman

Huettel

2012

Limnology & Ocean Methods

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Small gas bubbles embedded near the surface of submerged sand affect physical, chemical, and biological processes, and so their detection and characterization is important. So far, a noninvasive method for the detection of such bubbles has not been available. We developed a portable acoustic detection technique that offers high spatial and temporal resolution. The measuring system consists of a hand‐held ultrasonic transmitterreceiver that we operated with transducers generating 1 MHz and 2.27 MHz pulses. Bubble detection was based on changes in amplitude and travel time of backscatter data collected from bubbles that were either manually injected into sediment or created by sedimentary microalgal photosynthesis. Laboratory experiments showed that individual bubbles of 6 mm diameter can be detected as deep as 60 mm beneath the sediment‐water interface. Vertical and horizontal resolutions of 0.4–1 mm and 8–13 mm were achieved, depending on the transducer used. Measurements in a coastal bay demonstrated that our technique discriminates between sands with and without bubbles and locates embedded gas. We found that gas accumulations develop in the upper 10 mm of shallow sandy sediment in shallow water during daytime, revealing that the combination of photosynthetic oxygen production and porewater transport in permeable sands can lead to bubble generation below the photosynthetically active layer.

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Section: Laboratory Experimentssupporting

confidence: 45%

Section: Laboratory Experimentssupporting

confidence: 45%

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Wildman

Huettel

2012

Limnology & Ocean Methods

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“…Four types of mediums are considered: M1, water with glass beads; M2, aluminum block; M3, water; and M4, glass beads. The values of the physical parameters are given in Table III. small-diameter regime (kd << 1) while scattering prevails in the high-frequency or large-diameter regime (kd >> 1) [6], [11], [12]. As a consequence, to cover all situations, different types of modeling have to be considered.…”

Section: Different Physical and Numerical Modelsmentioning

confidence: 99%

“…The acoustic characteristics, such as the sound speed and the attenuation, can dramatically change with the ratio of the grain size to the wavelength [7]- [11]. Especially, as pointed out by Sessarego et al, when the wavelength is smaller than the grain size, the effect of scattering becomes very strong and can considerably affect the signal structure [12]. This grain size dependence makes the understanding of signals more difficult and engineers have to rely on an empirical method for the design of the new subbottom devices, which results in an increase in the total cost of the sea surveys.…”

mentioning

confidence: 99%

Numerical and Experimental Study of Wave Propagation in Water-Saturated Granular Media Using Effective Method Theories and a Full-Wave Numerical Simulation

Mizuno

Cristini

Komatitsch

et al. 2020

IEEE J. Oceanic Eng.

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In this article, the detection of an object buried in marine sediments is investigated. Using the results from a series of experiments realized in a tank filled with water and calibrated glass beads, we evaluate the performances for a wide range of the value of the ratio kd of the grain size to the wavelength (k is the wave number and d is the grain diameter) of three types of prediction tools. The first two prediction tools are based on the definition of an equivalent model. The first tool is based on the well-known Biot-Stoll theory (BM model) while the second tool uses nonperiodic homogenization to define effective velocity and anisotropy maps representing the medium (HM model). The last prediction tool implements a timedomain full-wave numerical method, which takes into account each grain separately (GM model). It is shown that a good agreement between experiments and numerical simulations can be achieved using the BM model for the low kd regime and the HM model for high kd regime.

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“…A similar inference concerning the importance of the discrete granular structure of sediments is even more justified when dealing with higher frequencies, as follows from recent laboratory experiments [19][20][21]. In some cases, one more mechanism of discrete scattering due to scatterers on the seafloor surface can also be important [22,23].…”

mentioning

confidence: 74%

Sound scattering by the seafloor: Results of recent theoretical and experimental research

Ivakin

2012

Acoust. Phys.

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Advancement in modern technologies for explora tion of the ocean and, in particular, the ocean shelf, requires methods for remote determination of various physical and geotechnical properties of the seafloor, its density, elasticity, particle size spectrum, as well as their spatial distribution on the seafloor surface and with depth. Acoustic waves reflected from and scat tered by the seafloor are natural carriers of such infor mation. This paper considers the current state of the oretical and experimental research on seafloor scatter ing. A brief review is given on results obtained and published in 1999-2010. Earlier results are available in reviews [1-6] and references therein.The results discussed in what follows relate mainly to two most recent major experiments, SAX99 [7-9] and SAX04 [10⎯12], on the sound scattering by the seafloor (these names are abbreviations of the Sedi ment Acoustics eXperiments 1999 and 2004). They were fulfilled at shallows of the Gulf of Mexico with roughly 20 m of water in about one kilometer from each other and off Fort Walton Beach, Florida. The main goal of the experiments was to test theoretical models describing different mechanisms of sound scattering by marine sediments. The scattering models support required interrelations among measurable characteristics of scattered field and various measur able physical parameters of the seafloor medium. Thus, to verify a model, it is necessary to have suffi ciently well controllable conditions, i.e., to perform simultaneous measurements of key input/output parameters of the model. Then, such models are appli cable for solving both direct (predicting scattering from a bottom with specified physical properties) and inverse problems of the acoustics of marine sediments (determination of seafloor properties from scattering data). Thus, these models are the basis for developing methods for acoustic sensing of the sediment.For example, sediment density, sound velocity along with the sound absorption coefficient within the seafloor, spatial spectra of irregularities of the seafloor surface (and/or interfaces) along with volumetric het erogeneity in the sediment body (or, in the case of dis crete scatterers, their size distributions) are the main input parameters needed to predict reverberation from the bottom. The frequency-angular dependences for the coefficients of sound reflection and scattering by the seafloor are the main output characteristics of such a model.During the SAX99 and SAX04 experiments, exten sive measurements of roughness spectra along with spectral and size analysis of particles from bottom samples have been performed by various techniques. This made it possible to estimate the spectrum of vol ume fluctuations of acoustic parameters in sediments (continuous inhomogeneities), the size and shape dis tribution function of discrete scatterers (mostly shells and their debris), as well as other seafloor parameters. Based on the available models [9,11,[13][14][15][16][17], this made it possible to calculate the contributions from v...

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Frequency Dependence of Phase Speed, Group Speed, and Attenuation in Water-Saturated Sand: Laboratory Experiments

Cited by 27 publications

References 22 publications

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Acoustic detection of gas bubbles in saturated sands at high spatial and temporal resolution

Numerical and Experimental Study of Wave Propagation in Water-Saturated Granular Media Using Effective Method Theories and a Full-Wave Numerical Simulation

Sound scattering by the seafloor: Results of recent theoretical and experimental research

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