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Title: Extraordinary acoustic transmission mediated by Helmholtz resonators

We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Computation Science Program, Middle Tennessee State University, Murfreesboro, Tennessee 37132 (United States)
  2. Department of Physics and Astronomy, Middle Tennessee State University, Murfreesboro, Tennessee 37132 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22299785
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 7; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; FREQUENCY DEPENDENCE; OPTICS; PHASE TRANSFORMATIONS; RESONATORS; SIMULATION; SOUND WAVES; TRANSMISSION; WAVELENGTHS