Rotating Rayleigh–Bénard convection and non-Boussinesq effects in pressurized SF₆

Rotating Rayleigh–Bénard convection (RBC) in pressurized sulfur hexafluoride (SF₆) with Prandtl number Pr=0.8 is investigated numerically based on direct numerical simulations (DNS) using finite-volume code GOLDFISH. A cylindrical cell of aspect ratio 1/2 (diameter-to-height) is considered, and the parameters studied are Rayleigh number from 10⁸ to 10¹⁰ and Rossby number Ro from 0.02 to 50.

Effects of temperature dependence of the fluid properties are investigated with wide range of temperature difference and the potential influence on global heat transfer, mean temperature profile and boundary layer thickness is explored.

Effects of rotating on the convection are analyzed in terms of global heat flux, long-term bulk temperature statistics, local historical temperature compared with the large-scale rotating RBC experiments in the "Uboot" of Göttingen of SF₆. The Nusselt number Nu is found to be in good agreement with the experimental data at various rotation rate.