Characterization of porous materials with a rigid frame via reflected waves

Abstract

The inverse problem for waves reflected by porous material is solved at oblique incidence, and an inverse scattering calculation of porosity and tortuosity is given for air-saturated plastic foam samples. The interaction of the sound pulse with the fluid-saturated porous material is described by a time-domain equivalent fluid model. The sensitivity of the porosity and tortuosity is studied and it shows their effect on the reflection coefficient at the first interface. This study shows that porosity is much more sensitive than tortuosity to reflection, especially when the incident angle is less than its critical value, at which the reflection coefficient vanishes. Some advantages and perspectives of this method are discussed.