Acoustic phenomena in porous media studied by transient grating spectroscopy: A critical test of the Biot theoryA. Taschin1, 2, R. Cucini1, 2, P. Bartolini1, 2 and R. Torre1, 2, 3
1 LENS, Università di Firenze - Via, N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy
2 INFM-CRS-Soft Matter (CNR), c/o Università la Sapienza - P.le A. Moro 2, I-00185, Roma, Italy
3 Dipartimento di Fisica, Università di Firenze - Via Sansone 1, I-50019 Sesto Fiorentino, Firenze, Italy
received 5 November 2007; accepted in final form 9 January 2008; published March 2008
published online 12 February 2008
Acoustic-wave propagation in liquid-filled porous glasses has been studied by a heterodyne detected transient grating experiment. A test of the Biot theory is presented under two new regimes, namely, for a new frequency range up to 1.3 GHz and for porous media with nanometric scale heterogeneities. We show that the Biot theory describes the sound velocity data correctly, but does not account for the acoustic attenuation. We suggest that the acoustic damping is mainly due to the dissipation mechanisms intrinsic of the matrix and the liquid which are not accounted for in the theory.
81.05.Rm - Porous materials; granular materials.
43.20.Jr - Velocity and attenuation of elastic and poroelastic waves.
78.47.jj - Transient grating spectroscopy.
© EPLA 2008