Transmission of ultrasonic waves through porous layers of high flow resistivity saturated by air

Transmission of ultrasonic waves through porous materials of high flow resistivity and porosity (in contact with air at both faces) is modelled and measured for an open-bubble foam at normal and oblique incidence. The importance of the airborne wave and the differences with the case of an elastic nonporous solid are demonstrated. A simple method to measure the shear modulus and the Poisson coefficient of the frame is suggested for similar materials.