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2009, 3

L. R. Yablonik

Acoustic modeling of dissipative silencers

language: Russian

received 24.02.2009, published 07.04.2009

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ABSTRACT

To study acoustic properties of dissipative silencers, a simulation of sound propagation in two-medium region is considered. The first medium is an ideal compressible fluid with density ro and sound velocity c. The second one is a sound-absorbing material with acoustic properties determined by flow resistivity r. In this case, the non-dimensional frequency characteristic of the silencer efficiency depends on a ratio between linear dimension of the structure and characteristic scale L=ro*c/r only. Universal characteristics of lengthy dissipative silencers with fibrous absorbers are obtained within the given approach. Two-parameter model, which takes into account the relation between channel width and sound-absorbing panel thickness, is analysed. The validity of the one-parameter model that describes a non-dimensional frequency characteristic in dependence of the channel width is confirmed for thick panels. Calculations for both cellular and isotropic packing of sound-absorbing material in the silencer in case of thick panels are performed.

Key words: dissipative silencer, simulation, calculation

13 pages, 6 figures

Сitation: L. R. Yablonik. Acoustic modeling of dissipative silencers. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2009, 3.

REFERENCES

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2. Морз Ф. Колебания и звук. М., Л., ГИТТЛ, 1949.
3. Mechel F. P. (Ed.). Formulas of Acoustics. Berlin Heidelberg, «Springer», 2004.
4. Справочник по технической акустике. Под редакцией Хекла М. и Мюллера Х. А. Л., «Судостроение», 1980.
5. Delany. M. E., Bazley E. N. Acoustical properties of fibrous absorbent materials. Applied Acoustics v.3, 1970, pp. 105-116.
6. Takeshi Komatsu. Improvement of the Delany-Bazley and Miki models for fibrous sound-absorbing materials. Acoust. Sci. & Tech. 29, 2 (2008), pp. 121-129.


 

Leonid R. Yablonik - Dr. Sci., Polzunov Central Boiler &Turbine Institute, St.Petersburg, Russia. Scientific interests: hydrodynamics, acoustics, vibrations.

e-mail: shum11(at)ckti.ru