A volume-based hydrodynamic approach to sound wave propagation in a monatomic gas

S. Kokou Dadzie*, Jason M. Reese

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We investigate sound wave propagation in a monatomic gas using a volume-based hydrodynamic model. In Dadzie et al. [Physica A 387, 6079 (2008)], a microscopic volume-based kinetic approach was proposed by analyzing molecular spatial distributions; this led to a set of hydrodynamic equations incorporating a mass-density diffusion component. Here we find that these new mass-density diffusive flux and volume terms mean that our hydrodynamic model, uniquely, reproduces sound wave phase speed and damping measurements with excellent agreement over the full range of Knudsen number. In the high Knudsen number (high frequency) regime, our volume-based model predictions agree with the plane standing waves observed in the experiments, which existing kinetic and continuum models have great difficulty in capturing. In that regime, our results indicate that the "sound waves" presumed in the experiments may be better thought of as "mass-density waves," rather than pressure waves.

Original languageEnglish
Article number016103
Number of pages11
JournalPhysics of Fluids
Issue number1
Publication statusPublished - Jan 2010

Keywords / Materials (for Non-textual outputs)

  • acoustic wave propagation
  • density
  • diffusion
  • Knudsen flow
  • Navier-Stokes equations
  • rarefied gas dynamics
  • kinetic theory
  • extended hydrodynamics
  • mass/volume diffusion
  • diffusive transport


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