Bubbling reduces intermittency in turbulent thermal convection

R. Lakkaraju, F. Toschi, Detlef Lohse

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Scopus)

Abstract

Intermittency effects are numerically studied in turbulent bubbling Rayleigh–Bénard (RB) flow and compared to the standard RB case. The vapour bubbles are modelled with a Euler–Lagrangian scheme and are two-way coupled to the flow and temperature fields, both mechanically and thermally. To quantify the degree of intermittency we use probability density functions, structure functions, extended self-similarity (ESS) and generalized extended self-similarity (GESS) for both temperature and velocity differences. For the standard RB case we reproduce scaling very close to the Obukhov–Corrsin values common for a passive scalar and the corresponding relatively strong intermittency for the temperature fluctuations, which are known to originate from sharp temperature fronts. These sharp fronts are smoothed by the vapour bubbles owing to their heat capacity, leading to much less intermittency in the temperature but also in the velocity field in bubbling thermal convection.
Original languageEnglish
Pages (from-to)1-24
Number of pages24
JournalJournal of fluid mechanics
Volume745
DOIs
Publication statusPublished - 2014

Keywords

  • IR-90673
  • METIS-303088

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