Transient sound radiated by spheres undergoing an elastic collision

Koss, L.L.; Alfredson, R.J.

doi:10.1016/0022-460x(73)90035-7

Cited by 47 publications

(24 citation statements)

References 1 publication

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“…The second condition is r/a 1, where r is the distance from the impacting spheres to the location at which the radiated sound is observed and a is the radius of the spheres; this condition can generally be readily adhered to. The pressure, P s (t), in the time domain for a single particle undergoing Hertzian impact (Goldsmith, 1960), with a half sine wave acceleration profile (Koss and Alfredson, 1973), can then be expressed as the convolution integral of the radiated pressure due to a unit impulse acceleration and the acceleration time history (Thorne and Foden, 1988); the solution is given by…”

Section: Theory For the Underwater Sound Generated By Impacting Spheresmentioning

confidence: 99%

“…The source arises from the impact of two or more particles as interparticle collisions occur as the bed becomes mobile and bedload transport occurs. The generation of sound by impacting bodies has primarily been examined in air, usually by parties interested in machine noise emissions (Banerji, 1916(Banerji, , 1918Koss and Alfredson, 1973;Koss, 1974a, b;Akay and Hodgson, 1978a, b;Akay, 1978). It is this work which was adapted for the study of acoustic radiation by colliding bodies underwater (Thorne and Foden, 1988;Thorne, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…It is this work which was adapted for the study of acoustic radiation by colliding bodies underwater (Thorne and Foden, 1988;Thorne, 1990). The source of radiation has been labelled rigid body radiation due to the origin of the pressure disturbance being generated by the acceleration of the body, rather than due to the natural modes of vibration of the body (Koss and Alfredson, 1973). To solve the problem, each sphere is treated as an independent source which generates a transient that can be described by an impulse solution convolved with the acceleration time history during the collision.…”

Section: Introductionmentioning

confidence: 99%

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An overview of underwater sound generated by interparticle collisions and its application to the measurements of coarse sediment bedload transport

Thorne

2014

Earth Surf. Dynam.

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Abstract. Over the past 2 to 3 decades the concept of using sound generated by the interparticle collisions of mobile bed material has been investigated to assess if underwater sound can be utilised as a proxy for the estimation of bedload transport. In principle the acoustic approach is deemed to have the potential to provide non-intrusive, continuous, high-temporal-resolution measurements of bedload transport. It has been considered that the intensity of the sound radiated should be related to the amount of mobile material and the frequency spectrum to the size of the material. To be able to fully realise this use of acoustics requires an understanding of the parameters which control the generation of sound as particles impact. In the present work the aim is to provide scientists developing acoustics to measure bedload transport with a description of how sound is generated when particles undergo collision underwater. To investigate the properties of the sound generated, examples are provided under different conditions of impact. It is considered that providing an overview of the origins of the sound generation will provide a basis for the interpretation of acoustic data, collected in the marine environment for the study of bedload sediment transport processes.

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Section: Theory For the Underwater Sound Generated By Impacting Spheresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An overview of underwater sound generated by interparticle collisions and its application to the measurements of coarse sediment bedload transport

Thorne

2014

Earth Surf. Dynam.

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“…In a mathematical sense, the acoustic pressure field generated from the acceleration of a rigid body is evaluated by the integral convolution from Eq. (1) (Akay and Hodgson, 1978;Koss and Alfredson, 1973;Thorne and Foden, 1988). The integral consists of the convolution between Kirchhoff's impulse response p I and an acceleration profile A.…”

Section: Introductionmentioning

confidence: 99%

“…where F (p I ) is the Fourier transform (FT) of Kirchhoff's impulse response p I (Koss and Alfredson, 1973), for a sphere of radius a, defined in Eq. (4b), F (A) the FT of Hertzian acceleration due to elastic impact between two identical radii and the same material spheres, defined in Eq.…”

Section: Introductionmentioning

confidence: 99%

Passive acoustic measurement of bedload grain size distribution using self-generated noise

Petrut¹,

Geay²,

Gervaise³

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Monitoring sediment transport processes in rivers is of particular interest to engineers and scientists to assess the stability of rivers and hydraulic structures. Various methods for sediment transport process description were proposed using conventional or surrogate measurement techniques. This paper addresses the topic of the passive acoustic monitoring of bedload transport in rivers and especially the estimation of the bedload grain size distribution from self-generated noise. It discusses the feasibility of linking the acoustic signal spectrum shape to bedload grain sizes involved in elastic impacts with the river bed treated as a massive slab. Bedload grain size distribution is estimated by a regularized algebraic inversion scheme fed with the power spectrum density of river noise estimated from one hydrophone. The inversion methodology relies upon a physical model that predicts the acoustic field generated by the collision between rigid bodies. Here we proposed an analytic model of the acoustic energy spectrum generated by the impacts between a sphere and a slab. The proposed model computes the power spectral density of bedload noise using a linear system of analytic energy spectra weighted by the grain size distribution. The algebraic system of equations is then solved by least square optimization and solution regularization methods. The result of inversion leads directly to the estimation of the bedload grain size distribution. The inversion method was applied to real acoustic data from passive acoustics experiments realized on the Isère River, in France. The inversion of in situ measured spectra reveals good estimations of grain size distribution, fairly close to what was estimated by physical sampling instruments. These results illustrate the potential of the hydrophone technique to be used as a standalone method that could ensure high spatial and temporal resolution measurements for sediment transport in rivers.

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Seabed Saltation Noise

Thorne

1993

Natural Physical Sources of Underwater Sound

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Transient sound radiated by spheres undergoing an elastic collision

Cited by 47 publications

References 1 publication

An overview of underwater sound generated by interparticle collisions and its application to the measurements of coarse sediment bedload transport

An overview of underwater sound generated by interparticle collisions and its application to the measurements of coarse sediment bedload transport

Passive acoustic measurement of bedload grain size distribution using self-generated noise

Seabed Saltation Noise

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