Flow states in two-dimensional Rayleigh-Bénard convection as a function of aspect-ratio and Rayleigh number

Erwin van der Poel, Richard Johannes Antonius Maria Stevens, K. Sugiyama, Detlef Lohse

Research output: Contribution to journalArticleAcademicpeer-review

39 Citations (Scopus)

Abstract

In this numerical study on two-dimensional Rayleigh-Bénard convection we consider 107 ⩽ Ra ⩽ 1012 in aspect-ratio 0.23 ⩽ Γ ⩽ 13 samples. We focus on several cases. First, we consider small aspect-ratio cells, where at high Ra number we find a sharp transition from a low Ra number branch towards a high Ra number branch, due to changes in the flow structure. Subsequently, we show that the influence of the aspect-ratio on the heat transport decreases with increasing aspect-ratio, although even at very large aspect-ratio of Γ ≈ 10 variations up to 2.5% in the heat transport as a function of Γ are observed. Finally, we observe long-lived transients up to at least Ra = 109, as in certain aspect-ratio cells we observe different flow states that are stable for thousands of turnover times.
Original languageEnglish
Article number085104
Number of pages12
JournalPhysics of fluids
Volume24
Issue number8
DOIs
Publication statusPublished - 2012

Keywords

  • METIS-290002
  • IR-82354

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