Experimental realization of extraordinary acoustic transmission using Helmholtz resonators
Experimental realization of extraordinary acoustic transmission using Helmholtz resonators
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DOI：
10.1063/1.4908180
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发表时间：
2015-02-01
期刊：
影响因子：
1.6
通讯作者：
Robertson, William M.
中科院分区：
文献类型：
--
作者：
Crow, Brian C.;Cullen, Jordan M.;Robertson, William M.
研究了声通过内置亥姆霍兹共振器（HR）的固体屏障时的异常声透射现象。亥姆霍兹共振器由一个嵌入式腔和两个突出的颈部组成，屏障的每一侧各有一个。在包含亥姆霍兹谐振器谐振频率的窄光谱范围内会发生非凡的传输。我们表明，97.5%的振幅传输是通过一个谐振器，其颈部创建一个总的障碍面积的6.25%的开放区域实现的。除了增强的传输，我们表明，有一个平稳的，连续的相变在传输的声音作为频率的函数。利用频率相关相变实验实现了以最大传输频率为中心的窄带高斯波包的慢波传输。使用并联对亥姆霍兹谐振器调谐到不同的谐振频率的实验探索作为一种手段，增加传输带宽。这些实验表明，由于相变，在两个亥姆霍兹共振频率之间总是存在一个频率，在该频率处，无论共振是接近还是远离，都发生相消干涉。最后，我们解释了如何与亥姆霍兹谐振器介导的非常声传输相关联的相变可以被利用来产生衍射声学组件，包括亚波长厚度的声透镜。(C)2015年作者。
The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier. Extraordinary transmission occurs for a narrow spectral range encompassing the resonant frequency of the Helmholtz resonator. We show that an amplitude transmission of 97.5% is achieved through a resonator whose neck creates an open area of 6.25% of the total barrier area. In addition to the enhanced transmission, we show that there is a smooth, continuous phase transition in the transmitted sound as a function of frequency. The frequency dependent phase transition is used to experimentally realize slow wave propagation for a narrow-band Gaussian wave packet centered at the maximum transmission frequency. The use of parallel pairs of Helmholtz resonators tuned to different resonant frequencies is experimentally explored as a means of increasing the transmission bandwidth. These experiments show that because of the phase transition, there is always a frequency between the two Helmholtz resonant frequencies at which destructive interference occurs whether the resonances are close or far apart. Finally, we explain how the phase transition associated with Helmholtz-resonator-mediated extraordinary acoustic transmission can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses. (C) 2015 Author(s).