Sound transmission of a spherical sound wave through a finite plate

AbstractTests done on specimens cut from the temporal bones show, that the stapedotomy can be more effective, if instead of the piston prosthesis, the ear chamber prosthesis is used. In that case, the vibrations of the eardrum are transferred to a plate with attachment sticked to the incus. The plate is suspended on a membrane stretched on the base of conical chamber which is filled with a fluid and placed in the middle ear cave. The sound wave caused by a vibrating plate, is focused at the chamber outlet placed in a small hole drilled in the stapes footplate. As in the case of the piston prosthesis behavior of the round window membrane differs from that observed in the normal ear. The flow through a narrow outlet of the conical chamber makes a more deflection of the central part of the round window membrane. The properties of the prosthesis elements are close to those of the removed parts of the middle ear. In spite of this, one can observe a different sound transmission inside the ear. When the sound is higher than 1000 Hz, the vibration amplitude of the plate is 5-10 dB higher than that for the stapes footplate in the healthy ear. However, when the sound is lower than 1000 Hz, this amplitude is lower than that for the stapes footplate. To explain it, a simplified model of the sound propagation in the ear given in the prior work is used. To get a better agreement with the test results, the model takes into account a damping of the sound wave by the round window membrane. Next, the model is adapted to the ear with chamber prosthesis. The factors that may have an effect on the behavior of the sound wave are examined. The first is shortening of the incus. It increases the leverage of the ossicles and the force acting on the prosthesis plate compared to that in the normal ear. Next factor is a reduction of the mass of the vibrating plate what makes a growth of its resonance frequency. This slightly reduces the amplitude of the plate for the low sounds and increases it for the medium and the higher sounds. At end, the lack of the influence of the flow through the conical chamber on the sound wave energy is shown. The assumed model gives the rules for amplitudes of the chamber plate as functions of the sound frequency. Their values for the sound frequency from 400 Hz to 8000 Hz and its graphs are shown and compared with those for the stapes footplate in the normal ear. One can see that if the sound frequency is higher than 1000 Hz, then the chamber prosthesis makes higher amplitudes of the sound wave than the normal ear. To explain their drop for frequencies lower than 1000 Hz, needs more tests in this range.

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Investigation of sound transmission properties of a medium resulting from sound wave compensation caused by other sound sources

Journal of Sound and Vibration ◽

10.1016/s0022-460x(70)80066-9 ◽

1970 ◽

Vol 11 (2) ◽

pp. 225-233 ◽

Cited By ~ 1

Author(s):

Stefan Czarnecki

Keyword(s):

Sound Wave ◽

Sound Transmission ◽

Sound Sources ◽

Transmission Properties

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Simulation of Sound Wave Propagation With Damping for Realistic Sound rendering for Games and Interactive Applications

PsycEXTRA Dataset ◽

10.1037/e582722013-020 ◽

2012 ◽

Author(s):

Bruno Moreira ◽

Mauricio Kischinhevsky ◽

Marcelo Zamith ◽

Esteban Clua ◽

Diego Brandao

Keyword(s):

Wave Propagation ◽

Sound Wave ◽

Interactive Applications ◽

Sound Rendering

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Technical Note. Influence of Material Used for the Regenerator on the Properties of a Thermoacoustic Heat Pump

Archives of Acoustics ◽

10.2478/aoa-2013-0067 ◽

2013 ◽

Vol 38 (4) ◽

pp. 565-570 ◽

Cited By ~ 2

Author(s):

Bartłomiej Kruk

Keyword(s):

Heat Transfer ◽

Temperature Gradient ◽

Acoustic Wave ◽

Heat Pump ◽

Sound Wave ◽

Heat Exchangers ◽

Heat Pumps ◽

Technical Note ◽

New Materials ◽

Modern Technologies

Abstract Research in termoacoustics began with the observation of the heat transfer between gas and solids. Using this interaction the intense sound wave could be applied to create engines and heat pumps. The most important part of thermoacoustic devices is a regenerator, where press of conversion of sound energy into thermal or vice versa takes place. In a heat pump the acoustic wave produces the temperature difference at the two ends of the regenerator. The aim of the paper is to find the influence of the material used for the construction of a regenerator on the properties of a thermoacoustic heat pump. Modern technologies allow us to create new materials with physical properties necessary to increase the temperature gradient on the heat exchangers. The aim of this paper is to create a regenerator which strongly improves the efficiency of the heat pump.

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