Heat transport by turbulent Rayleigh–Bénard convection for Pr ≃ 0.8 and 3 × 1012 ≲ Ra ≲ 1015: aspect ratio Γ = 0.50

We report on the experimental results for heat-transport measurements, in the form of the Nusselt number Nu, by turbulent Rayleigh–Bénard convection (RBC) in a cylindrical sample of aspect ratio 0 ≡ D/L = 0.50 (D = 1.12m is the diameter and L = 2.24m the height). The measurements were made using sulfur hexafluoride at pressures up to 19 bar as the fluid. They are for the Rayleigh-number range 3× 1012 . Ra . 1015 and for Prandtl numbers Pr between 0.79 and 0.86. For Ra < Ra 1 ' 1.4× 10 13 we find Nu = N0 Raeff with γeff = 0.312± 0.002, which is consistent with classical turbulent RBC in a system with laminar boundary layers below the top and above the bottom 7 Author to whom any correspondence should be addressed. Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercialShareAlike 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. New Journal of Physics 14 (2012) 103012 1367-2630/12/103012+39$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft