Heat Transport Scaling in Turbulent Rayleigh-Bénard Convection: Effects of Rotation and Prandtl Number

Abstract

We report experimental measurements of turbulent heat transport in rotating Rayleigh-B\'enard convection. The fluid was water with Prandtl number $3<\ensuremath{\sigma}<7$. Heat transport and local temperature measurements were made for Rayleigh numbers $2\ifmmode\times\else\texttimes\fi{}{10}^{5}<\mathrm{Ra}<5\ifmmode\times\else\texttimes\fi{}{10}^{8}$ and Taylor numbers $0\ensuremath{\le}\mathrm{Ta}\ensuremath{\le}5\ifmmode\times\else\texttimes\fi{}{10}^{9}$. For fixed convective Rossby numbers Ro between 0.1 and 1.5, the Nusselt number $N$ scaled closely as the 2/7 power of Ra but had very little variation with the Prandtl number $\ensuremath{\sigma}$ and only a moderate increase with increasing rotation rate. Substantial disagreement is found with existing scaling theories.