Ultrasonic method for Measuring transport parameters using only the reflected waves at the first interface of porous materials having a rigid frame

In this paper, acoustic method of direct problem for waves reflected at the first interface of porous materials saturated by air with rigid frame is solved at normal incidence in time domain. Simulated calculation using inverse problem is presented for determining the porosity, tortuosity, viscous and thermal characteristic length. The interaction of the sound pulse with the fluid-saturated porous material is described by an equivalent fluid model. The advantage of the proposed method is that the four parameters can be determined simultaneously. In addition, no relationship is assumed between the two characteristic lengths and without the required prior knowledge of the thickness of the porous material.