Pavel Urban, ISI Brno

Transition between different regimes of turbulent Rayleigh-Bénard convection at Rayleigh numbers of 1e10 – 1e11

We report experimental observation of transition between different regimes of turbulent Rayleigh-Bénard convection (RBC) at Rayleigh numbers of 1e10 – 1e11 and the Prandtl number Pr≈1. The transition was observed in both the power law scaling of the Nusselt number Nu(Ra) and the Reynolds number Re(Ra) associated with the large scale circulation of RBC. The values of Reynolds number were determined from time records of one-point and two-point temperature fluctuations, measured near the sidewalls at approximately mid-height of the aspect ratio one cell. Data on Re and Nu were collected simultaneously within one experiment.