Abstract
Measurements of dynamic compressibility of air-filled porous
sound-absorbing materials are compared with predictions involving
two parametere, the static thermal permeability k'_0 and the
thermal characteristic dimension GAMMA'. Emphasis on the notion of
dynamic and static thermal permeability - the latter being a
geometrical parameter equal to the inverse trapping constant ot
the solid frame - in apparently new.The static thermal
permeability plays, in the description of the thermal exchanges
between frame and saturating fluid, a role similar to the viscous
permeability in the desription of the viscous forces. Using both
parameters, a simple model is constructed for the dynamic thermal
permeability k', which is completely analogous to the Johnson et
al. [J. Fluid Mech. vol. 176, 379 (1987)] model of dynamic viscous
permeability k. The resultant modeling of dynamic compressibility
provides predictions which are closer to the experimental results
than the previously used simpler model where the compressibility
is the same as in identical circular cross-sectional shaped pores,
or distributions of slits, related to a given GAMMA'.
Original language | English |
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Journal | Acoustical Society of America. Journal |
Volume | 102 |
Issue number | 4 |
Pages (from-to) | 1995-2006 |
ISSN | 0001-4966 |
DOIs | |
Publication status | Published - 1997 |