×

Acoustic absorption of porous surfacing with dual porosity. (English) Zbl 0930.76079

Summary: We determine acoustic characteristics of a porous medium saturated by air. The analysis is performed using an homogenization technique; the macroscopic descriptions involve the effects of air viscosity, inertial forces and heat transfer. The first part of the paper deals with single porosity materials. Two cases are investigated: (i) a medium with large pores in which thermal exchanges are negligible; (ii) a medium with smaller pores for which thermal exchanges must be accounted for. The second part is concerned with dual porosity media, i.e. when the grains themselves are also porous. Neglecting heat transfer first yields a simplified macroscopic description. This simple dual porosity model is then improved by considered thermal effects. These results show that new porous materials could be evolved by introducing a microporosity that would give enhanced absorption properties over a wide range of frequencies.

MSC:

76Q05 Hydro- and aero-acoustics
76S05 Flows in porous media; filtration; seepage
35B27 Homogenization in context of PDEs; PDEs in media with periodic structure
80A20 Heat and mass transfer, heat flow (MSC2010)
PDFBibTeX XMLCite
Full Text: DOI