ABSTRACT
Transmission experiments are performed on highly porous materials saturated by different gases at ultrasonic frequencies up to 800 kHz. These measurements lead to fast and reliable methods to determine important acoustic parameters: the tortuosity α ∞ and the two characteristic lengths Λ and Λ’ that characterize the viscous and thermal interactions between the frame and the fluid. The parameters are deduced from the high frequency asymptotic behavior of either the velocity or the attenuation per cycle. Due to an excess attenuation mechanism, a high frequency limit of the classical models is observed.
