金属圆柱结构中声聚焦效应的研究

南京大学学报(自然科学版) ›› 2015, Vol. 51 ›› Issue (6): 1132–1138.

金属圆柱结构中声聚焦效应的研究

夏建平1，刘宸1，孙宏祥1, 2, 3*，张淑仪2，刘树森1，黄玉磊1

出版日期:2015-11-14 发布日期:2015-11-14
作者简介:1.江苏大学理学院,流体机械工程技术研究中心,镇江,212013;2.南京大学声学研究所,近代声学实验室,南京,210093;3.中国科学院声学研究所,声场声信息国家重点实验室,北京,100190
基金资助:
基金项目:国家重点基础研究发展计划(2012CB921504),国家自然科学基金(11174142,11404147),江苏省自然科学基金
(BK20140519),中国博士后基金(2015M571672),江苏大学高级人才基金(13JDG106),江苏大学青年骨干教师培养工
程,江苏省大学生实践创新训练项目(201510299047Y),江苏大学大学生实践创新训练项目,江苏大学科研立项,江苏大
学工业中心创新训练项目
收稿日期:2015-07-05
*通讯联系人,E-mail:jsdxshx@ujs.edu.cn

cylinder structure

Xia Jian-Ping1, Liu Chen1, Sun Hong-Xiang1, 2, 3, Zhang Shu-Yi2, Liu Shu-Sen1, Huang Yu-Lei1

Online:2015-11-14 Published:2015-11-14
About author:(1. Faculty of Science, Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, 212013, China; 2. Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing, 210093, China; 3. State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing, 100190, China)

摘要/Abstract

摘要： 研究浸没在水中金属空心圆柱结构的声聚焦效应及其物理机制,并探索声聚焦频率与圆柱结构参数之间的关系.研究表明:当超声波源从外侧入射到圆柱结构表面时,在圆柱结构中心会出现声聚焦效应.这种声聚焦效应源于金属圆柱结构中的位移本征模式,与之前研究利用负折射机制实现声聚焦效应完全不同,是一种全新的物理机制.在圆柱结构的位移本征模式作用下,入射声波的传播方向在圆柱结构内部发生重建,均沿着圆柱径向指向圆心,同时相位波形也呈现出同心圆分布,从而在圆柱结构中心聚焦成一个完美的圆形焦点,焦点在水平方向与垂直方向均表现出优异的聚焦性能.此外,基于声散射理论推导得到系统的特征方程,计算出声聚焦的特征频率,理论与数值结果符合很好.结果表明:圆柱结构可在多个频率出现声聚焦效应,相邻的两个声聚焦频率的间隔相同,且焦点的尺寸随着聚焦频率增加而变小.当金属圆柱结构的内外半径同时增大时,圆柱结构的声聚焦频率会减小,且声聚焦频率与圆柱的尺寸成反比关系.本研究为新型声聚焦器件的研制提供有效的设计思路及理论依据.

Abstract: In this paper, we study the exotic acoustic focusing effect through a simple brass cylinder structure immersed in water. Firstly, we calculate the acoustic pressure distributions with and without the brass cylinder, and the incident acoustic wave is emitted from the plane and cylindrical source, respectively. We find that the propagation directions of the acoustic waves are reconstructed by the cylinder and the acoustic waves are focused on a prefect point at the center of the cylinder structure. Meanwhile, the phase distributions are also reconstructed inside the cylinder, and the phase waveforms are transformed into a series of concentric circles with the same values and eventually focus on a point at the center of the cylinder. Besides, it is noted that the excellent acoustic focusing characteristics appear in both longitudinal and transverse directions, and the focal spot in the cylinder is a perfect point rather than an elliptical spot in other acoustic focusing devices. In addition, we present the deformation of the displacement distributions in the cylinder. It shows that the acoustic focusing arises from a special eigenmode in the cylinder structure at some eigenfrequencies, which is essentially distinct from the previous studies originating from the negative refraction. Finally, we derive the eigenvalue equations of the system according to the acoustic scattering theory, and theoretically calculate the eigenfrequencies. The numerical results agree well with the theoretical results. It is obtained that the acoustic focusing effect appears at a series of eigenfrequencies in the cylinder, and the difference between the two adjacent eigenfrequencies is a constant. Besides, the size of the focal spot decreases gradually with the increase of the focusing eigenfrequency. Furthermore, we investigate the influences of the structure parameters of the cylinder on the eigenfrequency, and find that the eigenfrequencis decrease with the increase of the inside and outside radii of the cylinder. Therefore, we conclude that there is an inverse relationship between the focusing eigenfrequency and the size of the cylinder. Our finding should have great potential applications in acoustic focusing devices

夏建平1，刘宸1，孙宏祥1, 2, 3*，张淑仪2，刘树森1，黄玉磊1. 金属圆柱结构中声聚焦效应的研究[J]. 南京大学学报(自然科学版), 2015, 51(6): 1132–1138.

Xia Jian-Ping1, Liu Chen1, Sun Hong-Xiang1, 2, 3, Zhang Shu-Yi2, Liu Shu-Sen1, Huang Yu-Lei1. cylinder structure[J]. Journal of Nanjing University(Natural Sciences), 2015, 51(6): 1132–1138.

参考文献

[1] 任悦，刘杰惠，刘晓宙等. 基于有限元分析的超声弹性成像仿真研究，南京大学学报(自然科学), 2015, 51(1): 7-13.
[2] Deng K, Ding Y Q, He Z J, et al. Graded negative index lens with designable focal length by phononic crystal. Journal of Physics D: Applied Physics,?2009, 42(18): 185505.
[3] Lin S C S, Huang T J, Sun J H, et al. Gradient-index phononic crystals. Physical Review B, 2009, 79(9): 094302.
[4] Martin T P, Nicholas M, Orris G J, et al. Sonic gradient index lens for aqueous applications. Applied Physics Letters, 2010, 97(11): 113503.
[5] Martin T P, Layman C N, Moore K M, et al. Elastic shells with high-contrast material properties as acoustic metamaterial components. Physical Review B, 2012, 85(16): 161103.
[6] Torrent D, Sánchez-Dehesa J. Acoustic metamaterials for new two-dimensional sonic devices. New journal of physics, 2007, 9(9): 323-335.
[7] Peng S S, He Z J, Zhang A Q, et al. Acoustic far-field focusing effect for two-dimensional graded negative refractive-index sonic crystals. Applied Physics Letters, 2010, 96(26): 263502.
[8] Zhang S, Yin L, Fang N. Focusing ultrasound with an acoustic metamaterial network. Physical Review Letters, 2009, 102(19): 194301.
[9] Zhou X, Hu G. Superlensing effect of an anisotropic metamaterial slab with near-zero dynamic mass. Applied Physics Letters, 2011, 98(26): 263510.
[10] Zigoneanu L, Popa B I, Cummer S A. Design and measurements of a broadband two-dimensional acoustic lens. Physical Review B, 2011, 84(2): 024305.
[11] Li Y, Liang B, Tao X, et al. Acoustic focusing by coiling up space. Applied Physics Letters, 2012, 101(23): 233508.
[12] Wang W, Xie Y, Konneker A, et al. Design and demonstration of broadband thin planar diffractive acoustic lenses. Applied Physics Letters, 2014, 105(10): 101904.
[13] He Z J, Jia H, Qiu C Y, et al. Acoustic transmission enhancement through a periodically structured stiff plate without any opening. Physical Review Letters, 2010, 105(7): 074301.
[14] Sun H X, Zhang S Y, Shui X J. A tunable acoustic diode made by a metal plate with periodical structure. Applied Physics Letters, 2012, 100(10): 103507.
[15] Sun H X, Zhang S Y. Enhancement of asymmetric acoustic transmission. Applied Physics Letters, 2013, 102(11): 113511.
[16] Xia J P, Sun H X. Acoustic focusing by metal circular ring structure. Applied Physics Letters, 2015, 106(6): 063505.
[17] Wei Q, Cheng Y, Liu X J. Acoustic omnidirectional superabsorber with arbitrary contour. Applied Physics Letters, 2012, 100(9): 094105.

Metrics

Viewed

Full text

Abstract

Cited

Shared

Discussed