Turbulent thermal diffusion in a multi-fan turbulence generator with imposed mean temperature gradient

A. Eidelman, T. Elperin, N. Kleeorin, I. Rogachevskii, I. Sapir-Katiraie

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24 Scopus citations

Abstract

We studied experimentally the effect of turbulent thermal diffusion in a multi-fan turbulence generator which produces a nearly homogeneous and isotropic flow with a small mean velocity. Using particle image velocimetry and image processing techniques, we showed that in a turbulent flow with an imposed mean vertical temperature gradient (stably stratified flow) particles accumulate in the regions with the mean temperature minimum. These experiments detected the effect of turbulent thermal diffusion in a multi-fan turbulence generator for relatively high Reynolds numbers. The experimental results are in compliance with the results of the previous experimental studies of turbulent thermal diffusion in oscillating grid turbulence (Buchholz et al. 2004; Eidelman et al. 2004). We demonstrated that the turbulent thermal diffusion is an universal phenomenon. It occurs independently of the method of turbulence generation, and the qualitative behavior of particle spatial distribution in these very different turbulent flows is similar. Competition between turbulent fluxes caused by turbulent thermal diffusion and turbulent diffusion determines the formation of particle inhomogeneities.

Original languageEnglish
Pages (from-to)744-752
Number of pages9
JournalExperiments in Fluids
Volume40
Issue number5
DOIs
StatePublished - 1 May 2006

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • General Physics and Astronomy
  • Fluid Flow and Transfer Processes

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