Viscous dissipative power density function for poroelastic saturated materials at high frequencies

Abstract

A viscous dissipative power density function is defined for poroelastic saturated materials at high frequencies. In the framework of Biot’s general theory of acoustics of poroelastic materials, the correction factor of the flow resistance of the fluid from low to high frequencies is derived from the power density function. For this aim the dissipative forces per unit volume are obtained from the viscous dissipative power density. The complex dynamic correction function of the viscosity is derived for the motion of a fluid limited by two parallel planes’ boundaries. It is also derived for the motion of a fluid in a cylindrical duct. Analytical solutions and impedance tube test results on air saturated porous metals are compared to validate the viscous dissipative power density up to frequencies of 6kHz. A second comparison is performed for kerosene saturated porous metals. Finally, a validation is performed using ultrasonic experiments on water saturated bones.