Optimal Prandtl number for heat transfer in rotating Rayleigh-Bénard convection

R.J.A.M. Stevens, H.J.H. Clercx, D. Lohse

Research output: Contribution to journalArticleAcademicpeer-review

44 Citations (Scopus)
84 Downloads (Pure)

Abstract

Numerical data for the heat transfer as a function of the Prandtl (Pr) and Rossby (Ro) numbers in turbulent rotating Rayleigh–Bénard convection are presented for Rayleigh number Ra=108. When Ro is fixed, the heat transfer enhancement with respect to the non-rotating value shows a maximum as a function of Pr. This maximum is due to the reduced effect of Ekman pumping when Pr becomes too small or too large. When Pr becomes small, i.e. for large thermal diffusivity, the heat that is carried by the vertical vortices spreads out in the middle of the cell and Ekman pumping thus becomes less effective. For higher Pr the thermal boundary layers (BLs) are thinner than the kinetic BLs and therefore the Ekman vortices do not reach the thermal BL. This means that the fluid that is sucked into the vertical vortices is colder than that for lower Pr, which limits the upwards heat transfer
Original languageEnglish
Article number07005
Pages (from-to)07005-1/8
Number of pages8
JournalNew Journal of Physics
Volume12
Issue number3
DOIs
Publication statusPublished - 2010

Fingerprint Dive into the research topics of 'Optimal Prandtl number for heat transfer in rotating Rayleigh-Bénard convection'. Together they form a unique fingerprint.

Cite this