Ultra-directional source of longitudinal acoustic waves based on a two-dimensional solid/solid phononic crystal

Morvan, Bruno; Tinel, Alain; Vasseur, J. O.; Sainidou, R.; Rembert, Pascal; Hladky‐Hennion, Anne‐Christine; Swinteck, N.; Deymier, Pierre A.

doi:10.1063/1.4903076

Cited by 29 publications

(16 citation statements)

References 19 publications

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“…This is because it is possible to engineer the band structure to constrain the wave to follow peculiar directions or to produce complete band gaps where wave propagation is forbidden. Resulting superlensing and self-collimation effects have been reported for electromagnetic [4,5], acoustic [6,7], and elastic [8,9] waves. More recently, the interest has been extended to the case of gravity water waves [10,11], because they share, in some limiting cases, the same wave equation as electromagnetic and acoustic waves.…”

Section: Introductionmentioning

confidence: 92%

Directional source of water waves by a crystal of surface-piercing cylinders

Chekroun

Maurel

Pagneux

et al. 2015

Comptes Rendus. Mécanique

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The feasibility of using the band structure of a crystal to realize directional emission of water waves is investigated numerically and experimentally. The directionality of a source inside a square array of cylinders is obtained numerically for a perfect lattice in a lossless liquid. But in the experiments, the directivity is weakened, due to the effects of losses. Nevertheless, the waves are shown to satisfy the Helmholtz equation when proper attenuation is accounted for. Thus, the robustness of the directionality is studied numerically with respect to the effects of the attenuation and of the disorder.© 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved. r é s u m é On étudie la faisabilité d'une source directive pour les ondes à la surface de l'eau, basée sur les propriétés de la structure de bandes d'un cristal. Cette directivité est caractérisée numériquement pour un réseau périodique de cylindres rigides dans un fluide parfait. Dans l'expérience, la directivité est affaiblie, à cause de l'atténuation. Cependant, en prenant en compte cette atténuation, la propagation des ondes est toujours correctement décrite par l'équation de Helmholtz. Aussi, la robustesse de la directivité est-elle étudiée numériquement plus en détail, vis-à-vis des effets d'atténuation et de désordre.Dans cette étude, la directivité d'une source d'émission placée dans un réseau périodique est étudiée, numériquement et expérimentalement, dans le contexte des ondes de gravité se propageant à la surface de l'eau. Si ces ondes satisfont, dans (M. Chekroun), agnes.maurel@espci.fr (A. Maurel), vincent.pagneux@univ-lemans.fr (V. Pagneux), phil@pmmh.espci.fr (P. Petitjeans). JID:CRAS2B AID:3357 /SSU [m3G; v1.159; Prn:17/07/2015; 18:06] P.2 (1-11) 2 M. Chekroun et al.des cas limites, une équation d'onde identique à celle vérifiée par les ondes acoustiques et par les ondes électromagnétiques en deux dimensions (l'équation de Helmholtz, Eq. (1)), elles présentent une complexité souvent négligée. Dispersives, non linéaires dans des conditions usuelles, susceptibles d'être affectées par des modes évanescents dans le volume du fluide dès que la bathymétrie du fond sous-marin varie brutalement, d'être affectées par le comportement de ménisques pour des obstacles émergeant hors de l'eau, les phénomènes attendus par simple inspection de l'équation de Helmholtz doivent être regardés avec vigilance au regard d'expériences qui diront si, oui ou non, ces phénomènes sont robustes. Dans ce papier, nous donnons des éléments de réponse à cette question dans le cas de l'hyper directivité prédite par Mei et al. [13] dans le contexte des ondes à la surface de l'eau. Pour ce faire, nous caractérisons, numériquement et expérimentalement, les ondes émergeant d'un réseau périodique (un cristal de taille finie) pour une fréquence en bord de bande, c'est-à-dire pour laquelle la structure de bandes prédit que seul un étroit faisceau d'onde peut s'échapper d'une structure périodique lorsqu'une source est placée en son centre. Cette directiv...

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Section: Introductionmentioning

confidence: 92%

Directional source of water waves by a crystal of surface-piercing cylinders

Chekroun

Maurel

Pagneux

et al. 2015

Comptes Rendus. Mécanique

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“…Cicek and his co-workers [27,28] studied numerically the wave propagation characteristics and self-collimation phenomenon of phononic crystals. Besides this, some experimental results have been performed to validate this phenomenon [29][30][31].…”

Section: Introductionmentioning

confidence: 93%

Elastic Wave Propagation of Two-Dimensional Metamaterials Composed of Auxetic Star-Shaped Honeycomb Structures

et al. 2019

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In this paper, the wave propagation in phononic crystal composed of auxetic star-shaped honeycomb matrix with negative Poisson's ratio is presented. Two types of inclusions with circular and rectangular cross sections are considered and the band structures of the phononic crystals are also obtained by the finite element method. The band structure of the phononic crystal is affected significantly by the auxeticity of the star-shaped honeycomb. Some other interesting findings are also presented, such as the negative refraction and the self-collimation. The present study demonstrates the potential applications of the star-shaped honeycomb in phononic crystals, such as vibration isolation and the elastic waveguide.

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“…Parallel zigzag rigid screens have also been proposed as potential focusing and directional beaming devices [28]. While the spatial filtering device described in this paper uses a fluid matrix, Morval et al [17] show directional enhancement of a monochromatic acoustic source into a surrounding water medium using a square array of cylinders in a solid matrix; the 2-dimensional quadropolar collimation effect is based on squareshaped equifrequency contours of the phononic crystal [34]. Although the solid matrix has obvious practical advantage, the narrow frequency device of [17] yields decreased amplitude in the preferential directions as compared with the free field radiation.…”

Section: Introductionmentioning

confidence: 99%

“…While the spatial filtering device described in this paper uses a fluid matrix, Morval et al [17] show directional enhancement of a monochromatic acoustic source into a surrounding water medium using a square array of cylinders in a solid matrix; the 2-dimensional quadropolar collimation effect is based on squareshaped equifrequency contours of the phononic crystal [34]. Although the solid matrix has obvious practical advantage, the narrow frequency device of [17] yields decreased amplitude in the preferential directions as compared with the free field radiation. The TA-based device described here does not have these limitations, and shows for the first time as far as we are aware, broadband positive gain in a neutrally buoyant square GRIN lens, with obvious implications for low loss underwater application.…”

Section: Introductionmentioning

confidence: 99%

A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements

Titovich

Norris

2016

The Journal of the Acoustical Society of America

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The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics (TA) of a circular region to a square dictates that the effective density in the lens remain constant and equal to that of water. Piecewise approximation to the desired effective compressibility is achieved using a square array with elements based on the elastic shell metamaterial concept developed in [30]. The size of the elements are chosen based on availability of shells, minimizing fabrication difficulties. The tested device is neutrally buoyant comprising 48 elements of nine different types of commercial shells made from aluminum, brass, copper, and polymers. Simulations indicate a broadband range in which the device acts as a cylindrical to plane wave lens. The experimental findings confirm the broadband quadropolar response from approximately 20 to 40 kHz, with positive gain of the radiation pattern in the four plane wave directions.

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Ultra-directional source of longitudinal acoustic waves based on a two-dimensional solid/solid phononic crystal

Cited by 29 publications

References 19 publications

Directional source of water waves by a crystal of surface-piercing cylinders

Directional source of water waves by a crystal of surface-piercing cylinders

Elastic Wave Propagation of Two-Dimensional Metamaterials Composed of Auxetic Star-Shaped Honeycomb Structures

A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements

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