Rayleigh - Bénard instability in sedimentation

Darrell Velegol, Shailesh Shori, Charles E. Snyder

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Instabilities often arise in the sedimentation of colloidal particles, even when using the density gradient technique. These instabilities occur at volume fractions as low as 10 -3 or 10 -4, causing mixing of particles throughout the suspension, rather than the smooth sedimentation of particles. Here, we show that the mixing is due to a classical Rayleigh-Bénard instability. The sedimentation process is modeled in an approximate manner, and experiments are done to test whether the approximate model gives maximum stable volume fractions in the correct range. Sedimentation is a well-studied problem, and yet, to our knowledge, this is the first time that the well-known instability has been described in terms of a Rayleigh-Bénard instability.

Original languageEnglish (US)
Pages (from-to)2414-2421
Number of pages8
JournalIndustrial and Engineering Chemistry Research
Issue number5
StatePublished - Mar 4 2009

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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