- Bliss, Donald B., STUDY OF BULK REACTING POROUS SOUND ABSORBERS AND A NEW BOUNDARY CONDITION FOR THIN POROUS LAYERS.,
Journal of the Acoustical Society of America, vol. 71 no. 3
pp. 533 - 545 .
(last updated on 2007/04/09)
The effect of bulk reaction on the sound absorption properties of porous materials is investigated theoretically and experimentally. Particular attention is focused on the important case of a layer of porous material attached to a rigid wall. In general, it is found that the surface of the porous material can be accurately represented by its normal incidence impedance only if a nondimensional flow resistance parameter is large, i. e. , only under this condition is the bulk reaction effect negligible. A new boundary condition is proposed which accounts for the effect of bulk reaction when the thickness of the sound absorbing layer is smaller than the acoustic wavelength. An experiment is conducted to demonstrate the importance of bulk reaction effects and to show that a method proposed to measure the bulk reaction coefficient is feasible.
POROUS MATERIALS - Acoustic Properties;