Measurements of temperature and velocity profiles in a convection cell of aspect ratio 1 at a Rayleigh number of 1.1×${10}^9$ and a Prandtl number (Pr) of 6.6 are presented. A large-scale flow persists in the cell. The temperature boundary layer is entirely contained in the viscous boundary layer and the velocity field is smooth on the characteristic length scale of temperature variations. The core of the cell is stably stratified. Most of the heat transported between the plates is carried by the general circulation and does not traverse the core of the cell. Comparison is made with observations at Pr=0.7.

• Received 17 December 1992

DOI:https://doi.org/10.1103/PhysRevE.47.R2253