Scattering Theory for Sound Absorption in Fibrous Media
作者:
K. Attenborough,
L. A. Walker,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1971)
卷期:
Volume 49,
issue 5A
页码: 1331-1338
ISSN:0001-4966
年代: 1971
DOI:10.1121/1.1912505
出版商: Acoustical Society of America
数据来源: AIP
摘要:
A simple model consisting of a random array of parallel elastic fibers in air is considered for the purpose of deducing the acoustic behavior of flexible porous media. A scattering analysis is employed and the mechanism of internal dissipation is thus interpreted as the irreversible mode conversion of incident dilatational waves into viscous and thermal waves by scattering at the fiber boundaries. The analysis is initially carried out for a dilute suspension such that the presence of the fiber scatterers is considered only to increase the attenuation of the imbedding fluid. This treatment is subsequently refined to include multiple scattering effects. Expressions for propagation constant, specific characteristic impedance, and surface normal impedance are deduced as functions of fiber radius, fiber concentration, and various physical constants of the fiber solid and air. The phenomenological parameters required in other theories are thus avoided. Furthermore, for a typical glass‐fiber material the multiple scattering theory is found to be in reasonable agreement with measurement.
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