Two-dimensional acoustic cloaks of arbitrary shape with layered structure based on transformation acoustics

Li, Qi; Vipperman, Jeffrey S.

doi:10.1063/1.4895765

Cited by 32 publications

(13 citation statements)

References 15 publications

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“…Cloaks with more complicated boundaries were then studied in the field of electromagnetism and acoustics. [37][38][39][40][41][42][43][44] These transforms were later introduced for heat diffusion fields. 45 The obtained heat cloaks were inhomogeneous and anisotropic which is diffcult to realize in practice.…”

Section: Introductionmentioning

confidence: 99%

Non-Singular Homogeneous Polyhedral Heat Cloak and Its Realization

Chen¹,

Liang²,

Laude³

et al. 2019

ES Energy Environ.

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As most arbitrarily shaped cloaks can be approximated by polyhedra and further divided into a series of tetrahedra, we propose in this paper a linear mapping approach to design cloaks with tetrahedron shapes (i. e. tetrahedral cloaks). Homogeneous material properties of the cloak are straightforwardly obtained from coordinates of typical points. Consequently, most arbitrarily shaped thermal cloaks can be designed using homogeneous anisotropic materials only. We construct two polyhedral cloaks and show numerically that they successfully thermally conceal objects after a certain lapse of time. We then demonstrate that cloaks with curved boundaries can also be obtained using our approach. It is further shown how geometrical parameters affect the material properties and cloaking performances. One can flexibly tune the cloaking performances based on practical requirements and material availabilities. We analyze effectiveness of a polygonal cloak composed of an alternation of homogeneous isotropic layers, and note that cloaking deteriorates at short times. We finally sketch an approach to realize 3D homogenized thermal metamaterials.

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Section: Introductionmentioning

confidence: 99%

Non-Singular Homogeneous Polyhedral Heat Cloak and Its Realization

Chen¹,

Liang²,

Laude³

et al. 2019

ES Energy Environ.

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“…One of those is the realization of a ground cloak through layers of isotropic materials. It has been showed that multilayered structure [23][24][25][26][27][28][29] is widely applied to design acoustic devices. However, few studies have investigated the realization of an acoustic ground cloak through layered structure composed of isotropic materials.…”

Section: Introductionmentioning

confidence: 99%

Design and assessment of an acoustic ground cloak with layered structure

Xiong

Chen

Wang

et al. 2015

Int. J. Mod. Phys. B

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In this paper, a two-dimensional acoustic ground cloak with alternating layered structure composed of mercury and water is designed on the basis of transformation acoustics and effective medium theory. The cloak exhibits excellent cloaking performance to hide an object from the detection of acoustic waves. Cosine similarity is proposed to precisely quantize and evaluate the cloaking performance, which turns out to be succinct and effective. Numerical simulations confirm that the cloak could work well in a broad frequency band in which the cloaking performance displays an oscillatory decrease with increasing frequency. In addition, the omnidirectional property, larger incident angle of the acoustic beam has the better cloaking performance, is analyzed. This multilayered structure of cloak may offer an access to fabrication simplicity and experimental demonstration. The concept of cosine similarity may be an enrichment of the assessment system for acoustic cloaks.

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“…Currently, many studies on invisibility cloaks, such as the optical, 1-4 electromagnetic, 5-8 acoustic, [9][10][11] and elastodynamic 12,13 cloaks based on wave fields, have been investigated by simulations and experiments. However, the research of thermal cloaks using diffuse fields has been a concern in recent years.…”

Section: Introductionmentioning

confidence: 99%

A concept of heat dissipation coefficient for thermal cloak based on entropy generation approach

Zhang

2016

AIP Advances

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In this paper, we design a 3D spherical thermal cloak with eight material layers based on transformation thermodynamics and it worked at steady state before approaching ‘static limit’. Different from the present research, we introduce local entropy generation to present the randomness in the cloaking system and propose the concept of a heat dissipation coefficient which is used to describe the capacity of heat diffusion in the ‘cloaking’ and ‘protected’ region to characterize the cloaking performance on the basis of non-equilibrium thermodynamics. We indicate the ability of heat dissipation for the thermal cloak responds to changes in anisotropy (caused by the change in the number of layers) and differential temperatures. In addition, we obtain a comparison of results of different cloaks and believe that the concept of a heat dissipation coefficient can be an evaluation criterion for the thermal cloak.

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Two-dimensional acoustic cloaks of arbitrary shape with layered structure based on transformation acoustics

Cited by 32 publications

References 15 publications

Non-Singular Homogeneous Polyhedral Heat Cloak and Its Realization

Non-Singular Homogeneous Polyhedral Heat Cloak and Its Realization

Design and assessment of an acoustic ground cloak with layered structure

A concept of heat dissipation coefficient for thermal cloak based on entropy generation approach

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