Abstract
The acoustic attenuation of acoustic fiber materials is mainly
determined by the dynamic resistivity to an oscillating air flow.
The dynamic resistance is calculated for a model with geometry
close to the geometry of real fibre material. The model constists
of parallel cylinders placed randomly. Two case are treated: flow
perpendicular to the cylinder axes, and flow parallel to the axes.
In each case two new approximate procedures were used. In the
first procedure, one solves the equation of flow in a Voronoi cell
around the fiber, and averages over the distribution of the
Voronoi cells.The second procedure is an extension to oscillating
air flow of the Brinkman self-consistent procedure for dc flow.
The procedures are valid for volume concentrations of cylinders
less than 0.1. The calculations show that for the density of
fibers of interest for acoustic fibre materials the simple
self-consistent procedure gives the same results as the more
complicated procedure based on average over Voronoi cells. Graphs
of the dynamic resistivity versus frequency are given for fiber
densities and diameters typical for acoustic fiber materials.
| Original language | English |
|---|---|
| Journal | Acoustical Society of America. Journal |
| Volume | 102 |
| Issue number | 3 |
| Pages (from-to) | 1680-1688 |
| ISSN | 0001-4966 |
| DOIs | |
| Publication status | Published - 1997 |