Sound propagation in the mixtures of liquid and solid aggregate; similarities at micro- and nanoscales.

Abstract

Sound propagation phenomena in certain liquid and solid aggregate mixtures, at micrometer scales, in some cases resemble the wave propagation behaviors of materials observed at nanometer and atomic scales. For example, it can be shown that the sound wave dispersion, attenuation, and cutoff-frequency effects depend on the same structural parameters as those observed at nano or atomic levels and are similar at both scales. Therefore, to investigate theoretical models of wave and matter interactions it is more convenient to use, as experimental tools, the readily analyzable models of wave propagation, in mixtures of solid and liquid, constructed at micrometer scales. Theoretical findings on sound propagation in the mixtures of liquid and solid particles at micrometer scales will be discussed. These results show the resemblance to the behavior of acoustic phonons, the lattice thermal vibrations of crystalline structures, at radically different scales. Experimental data on wave dispersion, attenuation, band-pass, and cutoff frequency effects, measured for sound propagation, in inhomogeneous materials consisting of mixtures of solid and liquid will be presented, showing the similarities of wave propagation behaviors at micro- and nanoscales.