Features of acoustic emission caused by gas filtration through highly permeable porous media

Abstract

Mechanical loading and filtration of fluids in porous media leads to acoustic emission. The spectra of such signals depend on the loading mode and the physical properties of porous media. In this work, we investigated the acoustic emission spectra of highly permeable porous samples during filtration through air. The characteristic features of the obtained spectra have been established. In particular, it was shown that the recorded noise signal at low Re numbers consists of individual pulses with a duration of about 25 ms, uniformly distributed in frequency. With an increase in the filtration rate, these pulses are concentrated near the characteristic peaks, which is what determines the final spectrum of the porous sample. The obtained new experimental data can be used in the development of a unified theory of noise generation in saturated porous media.