Sound propagation in phase-separating fluids (original) (raw)

Dispersion of acoustic excitations in tetrahedral liquids

Journal of Physics: Condensed Matter, 2020

Investigation of the longitudinal and transverse excitations in liquids is of great importance for understanding the fundamentals of the liquid state of matter. One of the important questions is the temperature and density dependence of the frequency of the excitations. In our recent works it was shown that while in simple liquids the frequency of longitudinal excitations increases when the temperature is increased isochorically, in water the frequency can anomalously decrease with the temperature increase. In the present manuscript we study the dispersion curves of longitudinal and transverse excitations of water and liquid silicon modelled by Stillinger-Weber potential. We show that both substances demonstrate the anomaly of the dispersion curves, but it the case of water it is more pronounced.

Resolving the puzzle of sound propagation in liquid helium at low temperatures

Low Temperature Physics, 2019

Experimental data suggests that, at temperatures below 1 K, the pressure in liquid helium has a cubic dependence on density. Thus the speed of sound scales as a cubic root of pressure. Near a critical pressure point, this speed approaches zero whereby the critical pressure is negative, thus indicating a cavitation instability regime. We demonstrate that to explain this dependence, one has to view liquid helium as a mixture of three quantum Bose liquids: dilute (Gross-Pitaevskii-type) Bose-Einstein condensate, Ginzburg-Sobyanin-type fluid, and logarithmic superfluid. Therefore, the dynamics of such a mixture is described by a quantum wave equation, which contains not only the polynomial (Gross-Pitaevskii and Ginzburg-Sobyanin) nonlinearities with respect to a condensate wavefunction, but also a non-polynomial logarithmic nonlinearity. We derive an equation of state and speed of sound in our model, and show their agreement with experiment.

On sound dispersion and attenuation in simple and multi-fluids due to thermal and viscous effects

Proceedings of Meetings on Acoustics

In this paper, we first present an approach to derive the dispersion relation for sound waves in viscous and thermally conductive (mono) fluids. In particular, we derive a dispersion expression (i.e. the variation of the sound velocity as a function of frequency), which is of the second order of magnitude with respect to Knudsen numbers, as in the Stokes case corresponding to a non-conducting fluid (infinite Prandtl number). This formula completes the classical attenuation relation called Stokes-Kirchhoff. 1 In the second part, we present some models for two fluids mixtures, 10 and derive the effect of viscosity on the dispersion and attenuation of sound. In addition, we show how this approach can be used to discriminate multiphase models that do not reproduce physically meaningful sound propagation velocities.

Waves in bubbly liquids with phase change

International Journal of Engineering Science, 2001

In a previous paper (C. Boutin, J.-L. Auriault, Acoustics of a bubbly¯uid at large bubble concentration, Eur. J. Mech. B/Fluids, 12(3) (1993) 367±399), the homogenization technique was used to investigate how acoustic waves propagate in a bubbly¯uid at ®nite concentration. Three dierent equivalent macroscopic behaviours were shown to exist, for``large''-,``medium''-and``small''-size bubble systems, respectively. In the present paper, we extend the analysis by taking into consideration possible phase change eects. We show that phase change eects are negligible in the case of large-size bubbles, whereas they strongly modify the medium-size bubble system behaviour. For small-size bubbles capillarity dominates the process. Ó