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Title: Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

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 transmissionmore » can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses.« less
Authors:
; ;  [1] ;  [2] ;  [1] ;  [3]
  1. Department of Physics and Astronomy, Middle Tennessee State University, Murfreesboro, Tennessee 37132 (United States)
  2. Computational Science Program, Middle Tennessee State University, Murfreesboro, Tennessee 37132 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22454449
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 2; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; FREQUENCY DEPENDENCE; PHASE TRANSFORMATIONS; RESONANCE; RESONATORS; SOLIDS; SOUND WAVES; TRANSMISSION; WAVE PROPAGATION; WAVELENGTHS