Non-reciprocal acoustics in a viscous environment

It is demonstrated that acoustic transmission through a phononic crystal with anisotropic solid scatterers becomes non-reciprocal if the background fluid is viscous. In an ideal (inviscid) fluid, the transmission along the direction of broken P symmetry is asymmetric. This asymmetry is compatible with reciprocity since time-reversal symmetry ( T symmetry) holds. Viscous losses break T symmetry, adding a non-reciprocal contribution to the transmission coefficient. The non-reciprocal transmission spectra for a phononic crystal of metallic circular cylinders in water are experimentally obtained and analysed. The surfaces of the cylinders were specially processed in order to weakly break P symmetry and increase viscous losses through manipulation of surface features. Subsequently, the non-reciprocal part of transmission is separated from its asymmetric reciprocal part in numerically simulated transmission spectra. The level of non-reciprocity is in agreement with the measure of broken P symmetry. The reported study contradicts commonly accepted opinion that linear dissipation cannot be a reason leading to non-reciprocity. It also opens a way for engineering passive acoustic diodes exploring the natural viscosity of any fluid as a factor leading to non-reciprocity.

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Thermal tuning of acoustic transmission enhancement through a phononic crystal slab

2013 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications ◽

10.1109/spawda.2013.6841151 ◽

2013 ◽

Author(s):

Chao-wei Xu ◽

Fei-yan Cai ◽

Shu-hong Xie ◽

Jiang-yu Li ◽

Hai-rong Zheng

Keyword(s):

Phononic Crystal ◽

Acoustic Transmission ◽

Transmission Enhancement ◽

Thermal Tuning

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Research on the large band gaps in multilayer radial phononic crystal structure

Modern Physics Letters B ◽

10.1142/s0217984916501098 ◽

2016 ◽

Vol 30 (10) ◽

pp. 1650108 ◽

Cited By ~ 1

Author(s):

Nansha Gao ◽

Jiu Hui Wu ◽

Dong Guan

Keyword(s):

Crystal Structure ◽

Finite Element Method ◽

Phononic Crystal ◽

Phononic Crystals ◽

Band Gaps ◽

Transmission Spectra ◽

Intermediate Mass ◽

Displacement Fields ◽

Vibration Coupling ◽

Single Material

In this paper, we study the band gaps (BGs) of new proposed radial phononic crystal (RPC) structure composed of multilayer sections. The band structure, transmission spectra and eigenmode displacement fields of the multilayer RPC are calculated by using finite element method (FEM). Due to the vibration coupling effects between thin circular plate and intermediate mass, the RPC structure can exhibit large BGs, which can be effectively shifted by changing the different geometry values. This study shows that multilayer RPC can unfold larger and lower BGs than traditional phononic crystals (PCs) and RPC can be composed of single material.

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Underwater unidirectional acoustic transmission through a plate with bilateral asymmetric gratings

Modern Physics Letters B ◽

10.1142/s0217984918501336 ◽

2018 ◽

Vol 32 (11) ◽

pp. 1850133 ◽

Cited By ~ 2

Author(s):

Ailing Song ◽

Tianning Chen ◽

Xiaopeng Wang ◽

Yanhui Xi ◽

Qingxuan Liang

Keyword(s):

Displacement Field ◽

Slit Width ◽

Transmission Spectra ◽

Acoustic Transmission ◽

The Finite Element Method ◽

Acoustic Intensity ◽

Field Distributions ◽

Intensity Field ◽

Potential Applications ◽

Ultrasonic Devices

In this paper, a novel underwater unidirectional acoustic transmission (UAT) device consisting of a plate with bilateral asymmetric gratings is proposed and numerically investigated. The transmission spectra, the acoustic intensity field distributions, and the displacement field distributions are numerically calculated based on the finite element method. The transmission spectra show that the proposed device exhibits different UAT effects in three bands. The acoustic intensity field distributions demonstrate that the proposed device can realize UAT, which agree well with the transmission spectra. The mechanism is discussed by analyzing the displacement field distributions, and the UAT is attributed to the symmetric mode excited in brass plate. Furthermore, the effects of the lattice constant, the upper slit width, and the lower slit width on bands are discussed. Our design provides a good reference for designing underwater UAT devices and has potential applications in some fields, such as medical ultrasonic devices, acoustic barrier, and noise insulation.

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Non-existence of an Inviscid Fluid Motion between Two Fixed Cylinders

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v34i1.5494 ◽

1970 ◽

Vol 34 (1) ◽

pp. 83-87

Author(s):

M Jalal Ahammad

Keyword(s):

Stream Function ◽

Fluid Motion ◽

Circular Cylinders ◽

Inviscid Fluid ◽

Academy Of Sciences

A problem on the plane inviscid and irrotational fluid motion due to the presence of a linesource and sink in the region between two fixed co-axial circular cylinders is considered in terms ofthe stream function. It has been shown that the solution of the problem is not possible in the light ofthe Eulerian theory of inviscid fluid motion.Key words: Non-existence; Inviscid fluid motion; Fixed cylinderDOI: 10.3329/jbas.v34i1.5494Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 83-87, 2010

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Application of time reversal to passive acoustic remote sensing of the ocean

Acoustical Physics ◽

10.1134/s1063771017020038 ◽

2017 ◽

Vol 63 (3) ◽

pp. 309-320 ◽

Cited By ~ 4

Author(s):

O. A. Godin ◽

B. G. Katsnelson ◽

Jixing Qin ◽

M. G. Brown ◽

N. A. Zabotin ◽

...

Keyword(s):

Remote Sensing ◽

Time Reversal ◽

Acoustic Remote Sensing ◽

Passive Acoustic

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Hydrodynamic interactions among multiple circular cylinders in an inviscid flow

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.434 ◽

2012 ◽

Vol 712 ◽

pp. 505-530 ◽

Cited By ~ 2

Author(s):

R. Sun ◽

C. O. Ng

Keyword(s):

Boundary Value Problem ◽

Numerical Solutions ◽

Boundary Value ◽

Cyclic Permutation ◽

Neumann Boundary ◽

Hydrodynamic Interactions ◽

Circular Cylinders ◽

Constructive Method ◽

Nonlinear Phenomena ◽

Inviscid Fluid

AbstractHydrodynamic interactions among multiple circular cylinders translating in an otherwise undisturbed inviscid fluid are theoretically investigated. A constructive method for solving a Neumann boundary-value problem in a domain outside $N$ circles (one kind of Hilbert boundary-value problem in the complex plane) is presented in the study to derive the velocity potential of the liquid. The method employs successive offset functions combined with a ‘generalized cyclic permutation’ in turn to satisfy the impenetrable boundary condition on each circle. The complex potential is therefore expressed as $N$ isolated singularities in power series form and used to get instantaneous added masses of $N$ submerged circular cylinders. Then, based on the Hamilton variational principle, a dynamical equation of motion in vector form is derived to predict nonlinear translations of the submerged bodies under fully hydrodynamic interactions. Also, the equivalence of the energy-based Lagrangian framework and a momentum-type one in the two-dimensional body–liquid system is proved. It implies that the pressure integration around a submerged body is holographic, which provides information about velocities and accelerations of all bodies. The numerical solutions indicate some typical dynamical behaviours of more than two circular cylinders which reveal that interesting nonlinear phenomena would appear in such a system with simple physical assumptions.

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Band structures in a two-dimensional phononic crystal with rotational multiple scatterers

International Journal of Modern Physics B ◽

10.1142/s0217979217500382 ◽

2017 ◽

Vol 31 (06) ◽

pp. 1750038 ◽

Cited By ~ 4

Author(s):

Ailing Song ◽

Xiaopeng Wang ◽

Tianning Chen ◽

Lele Wan

Keyword(s):

Sound Pressure ◽

Phononic Crystal ◽

Low Frequency ◽

Electrical Circuit ◽

Frequency Noise ◽

Transmission Spectra ◽

Two Dimensional ◽

Band Structures ◽

Unit Cells ◽

Circuit Analogy

In this paper, the acoustic wave propagation in a two-dimensional phononic crystal composed of rotational multiple scatterers is investigated. The dispersion relationships, the transmission spectra and the acoustic modes are calculated by using finite element method. In contrast to the system composed of square tubes, there exist a low-frequency resonant bandgap and two wide Bragg bandgaps in the proposed structure, and the transmission spectra coincide with band structures. Specially, the first bandgap is based on locally resonant mechanism, and the simulation results agree well with the results of electrical circuit analogy. Additionally, increasing the rotation angle can remarkably influence the band structures due to the transfer of sound pressure between the internal and external cavities in low-order modes, and the redistribution of sound pressure in high-order modes. Wider bandgaps are obtained in arrays composed of finite unit cells with different rotation angles. The analysis results provide a good reference for tuning and obtaining wide bandgaps, and hence exploring the potential applications of the proposed phononic crystal in low-frequency noise insulation.

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Low-frequency bandgaps of two-dimensional phononic crystal plate composed of asymmetric double-sided cylinder stubs

International Journal of Modern Physics B ◽

10.1142/s0217979216500296 ◽

2016 ◽

Vol 30 (07) ◽

pp. 1650029 ◽

Cited By ~ 9

Author(s):

Ailing Song ◽

Xiaopeng Wang ◽

Tianning Chen ◽

Ping Jiang ◽

Kai Bao

Keyword(s):

Phononic Crystal ◽

Low Frequency ◽

Resonant Mode ◽

Dispersion Relations ◽

Transmission Spectra ◽

Two Dimensional ◽

The Finite Element Method ◽

Frequency Range ◽

Displacement Fields ◽

Band Structures

In this paper, we theoretically investigate the propagation characteristics of Lamb wave in a two-dimensional (2D) asymmetric phononic crystal (PC) plate composed of cylinder stubs of different radius deposited on both sides of a thin homogeneous plate. The dispersion relations, transmission spectra and displacement fields of the eigenmodes are calculated by using the finite element method (FEM). Two complete bandgaps (BGs) can be found in low-frequency range and the transmission spectra coincide with the band structures. We investigate the evolution of dispersion relations with the decrease of the upper stub radius. The physical mechanism of the upper stub radius effect is also studied with the displacement fields of the unit cell. Numerical results show that the symmetry of the stub radius can remarkably influence the band structures and the asymmetric double-sided plate exhibits a new bandgap (BG) in lower frequency range due to the coupling between the lower stub’s resonant mode and the plate’s Lamb mode becomes weak and the adjacent bands separate. Moreover, we further investigate the effect of the stub height on the dispersion relations and find that the BGs shift to lower frequency regions with the increase of the stub height. In addition, the BGs’ sensitivity to the upper stub radius and the stub height is discussed. The low-frequency BGs in the proposed PC plate can potentially be used to control and insulate vibration in low frequency range.

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