Wave Transmission through Porous Structures

Assuming long, normally incident waves on a homogeneous porous structure of rectangular cross section, a simple explicit solution for the transmission and reflection coefficients are obtained from a linearized theory. The relationship between the nonlinear flow resistance in the porous medium and its equivalent linear form is obtained in explicit form. Empirical relationships for the nonlinear flow resistance are reviewed and are shown to lead to acceptable estimates of the hydraulic properties of a porous medium. Using the empirical relationships for the hydraulic properties of a porous material in conjunction with the explicit simple solution for the reflection and transmission coefficients leads to results comparable to the results of other more time-consuming procedures.