Acoustic resonances of thin cylindrical shells and the resonance scattering theory

Talmant, Maryline; Quentin, G.; Rousselot, J. L.; Subrahmanyam, J. V.; Überall, H.

doi:10.1121/1.396847

Cited by 38 publications

(12 citation statements)

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“…3(b) [2,3,25]. These peaks are due to the resonances of modes n, they are connected with the propagation of circumferential waves [3,13,27]. When a circumferential wave is generated on the shell, a resonance establishes when the number of wavelengths on the circumference of the tube is an integer, this integer is the mode n. To plot the figure 3(c), the resonance spectra are calculated for each values of n with the previously technique and associated in a plane "n-k 1 a" with amplitude in grey level.…”

Section: Backscattered Acoustic Signal From a Tubementioning

confidence: 98%

“…Among all the targets of simple geometrical forms (plate, cylinder, sphere, tube...), tubes are the subject of few studies of characterization [1][2][3][4][5][6][7][8][9][10][11][12]. If an air-filled tube immersed in water is excited by a plane acoustic wave perpendicularly to its axis, circumferential waves are generated in the shell and in the water/shell interface [13,14]. For some frequencies, these circumferential waves form stationary waves on the circumference of the tube constituting resonances [14].…”

Section: Introductionmentioning

confidence: 99%

“…These resonances are observed on the spectrum of the acoustic pressure backscattered (or the form function) by the tube [3,5]. The circumferential waves can belong to two wave types which are equivalent to the Lamb waves on a plate if the shell wall is thin: the anti-symmetric (A i ) and symmetric (S i ) circumferential waves (i = 0, 1, 2, …: index of wave) [5,9,13].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Neuro-fuzzy Computing Technique for Modeling the Acoustic Form Function of Immersed Tubes

Nahraoui¹,

Aassif²,

Elhanaoui³

et al. 2013

IJCA

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An Adaptative Neuro-Fuzzy Inference System (ANFIS) is developed to predict the acoustic form function (FF) for an infinite length cylindrical shell excited perpendicularly to its axis. The Wigner-Ville distribution (WVD) is used like a comparison tool between the calculated FF by the analytical method and that predicted by the neuro-fuzzy technique for a copper tube. During the application of this technique, several configurations are evaluated for various radius ratio b/a (a: outer radius, b: inner radius of tube). This neuro-fuzzy technique is able to predict the FF with a mean relative error (MRE) about 1.7%.

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Section: Backscattered Acoustic Signal From a Tubementioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Neuro-fuzzy Computing Technique for Modeling the Acoustic Form Function of Immersed Tubes

Nahraoui¹,

Aassif²,

Elhanaoui³

et al. 2013

IJCA

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“…With f descending towards the coincidence frequency where c(A 0 ) approaches c w , the coupling takes effect, causing the previously converging A 0 and A curves to undergo a ''repulsion. '' 15 During this repulsion the physical nature of the two waves switches around, 18 so that at still lower frequencies ͑below coincidence͒, A now is a shellborne and A 0 a fluid-borne wave. The switch-over of the physical character of modes during curve repulsions as caused by modal coupling is also known in other branches of physics, e.g., in atomic physics.…”

Section: -11mentioning

confidence: 99%

Circumferential-wave phase velocities for empty, fluid-immersed spherical metal shells

Überall

Ahyi

Raju

et al. 2002

The Journal of the Acoustical Society of America

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In earlier studies of acoustic scattering resonances and of the dispersive phase velocities of surface waves that generate them ͓see, e.g., Talmant et al., J. Acoust. Soc. Am. 86, 278 -289 ͑1989͒ for spherical aluminum shells͔ we have demonstrated the effectiveness and accuracy of obtaining phase velocity dispersion curves from the known acoustic resonance frequencies. This possibility is offered through the condition of phase matching after each complete circumnavigation of these waves ͓Ü berall et al., J. Acoust. Soc. Am. 61, 711-715 ͑1977͔͒, which leads to a very close agreement of resonance results with those calculated from three-dimensional elasticity theory whenever the latter are available. The present investigation is based on the mentioned resonance frequency/elasticity theory connection, and we obtain comparative circumferential-wave dispersion-curve results for water-loaded, evacuated spherical metal shells of aluminum, stainless steel, and tungsten carbide. In particular, the characteristic upturn of the dispersion curves of low-order shell-borne circumferential waves ͑A or A 0 waves͒ which takes place on spherical shells when the frequency tends towards very low values, is demonstrated here for all cases of the metals under consideration.

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“…3, primarily at and below the coincidence frequency at mid to high angles might be better associated with the slightly subsonic a 0Ϫ wave, which has been shown to lead to large backscattering enhancements from spherical and right-circular cylindrical shells. 18,19 The dashed curves in Fig. 3͑c͒ show the resonance loci for helical propagation of the a 0Ϫ wave, calculated using Eq.…”

mentioning

confidence: 99%

High-frequency backscattering enhancements by thick finite cylindrical shells in water at oblique incidence: Experiments, interpretation, and calculations

Morse

Marston

Kaduchak³

1998

The Journal of the Acoustical Society of America

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Impulse response backscattering measurements are presented and interpreted for the scattering of obliquely incident plane waves by air-filled finite cylindrical shells immersed in water. The measurements were carried out to determine the conditions for significant enhancements of the backscattering by thick shells at large tilt angles. The shells investigated are made of stainless steel and are slender and have thickness to radius ratios of 7.6% and 16.3%. A broadband PVDF ͑polyvinylidene fluoride͒ sheet source is used to obtain the backscattering spectral magnitude as a function of the tilt angle ͑measured from broadside incidence͒ of the cylinder. Results are plotted as a function of frequency and angle. These plots reveal large backscattering enhancements associated with elastic excitations at high tilt angles, which extend to end-on incidence in the coincidence frequency region. Similar features are present in approximate calculations for finite cylindrical shells based on full elasticity theory and the Kirchhoff diffraction integral. One feature is identified as resulting from the axial ͑meridional ray͒ propagation of the supersonic a 0 leaky Lamb wave. A simple approximation is used to describe circumferential coupling loci in frequency-angle space for several surface waves. The resulting loci are used to identify enhancements due to the helical propagation of the subsonic a 0Ϫ Lamb wave. © 1998 Acoustical Society of America. ͓S0001-4966͑98͒04302-1͔PACS numbers: 43.30.Gv, 43.20.Fn ͓DLB͔ INTRODUCTIONRecent high-frequency sonar images of truncated cylindrical shells indicate that the visibility of the ends of the shell can be improved by an elastic response of the shell.1 The enhancements are associated with a category of lth class of leaky ray shown in Fig. 1. The enhancement occurs when the tilt angle ␥ of the cylinder is close to the leaky wave coupling angle l ϭsin Ϫ1 (c/c l ), where c l is the phase velocity of the leaky wave and c is the speed of sound in the surrounding water. This ray is referred to as a meridional ray 2 since it is propagated along the meridian defined by the direction of the incident wave vector and the cylinder's axis. An analysis shows that the backscattering enhancement is associated with the vanishing of Gaussian curvature of the wavefront backscattered in the direction of the receiver. The enhancements reported 1 were for tilts in the vicinity of 18°and 35°corre-sponding to the excitation of symmetric and antisymmetric (s 0 and a 0 ͒ generalizations of leaky Lamb waves on the stainless steel cylinder used in those experiments. The purpose of the present paper is to document the existence of high-frequency backscattering enhancements for tilted cylindrical shells relevant to larger values of the tilt ␥ and in some cases, extending to ␥ϭ90°͑i.e., end-on incidence͒.The method of our investigation concerns the global response in the frequency-angle domain rather than the spatial responses emphasized in Ref.1. There are several reasons for identifying such high-frequency enhancement...

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Acoustic resonances of thin cylindrical shells and the resonance scattering theory

Cited by 38 publications

References 0 publications

A Neuro-fuzzy Computing Technique for Modeling the Acoustic Form Function of Immersed Tubes

A Neuro-fuzzy Computing Technique for Modeling the Acoustic Form Function of Immersed Tubes

Circumferential-wave phase velocities for empty, fluid-immersed spherical metal shells

High-frequency backscattering enhancements by thick finite cylindrical shells in water at oblique incidence: Experiments, interpretation, and calculations

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