Container shape dependence of heat transport in high Prandtl number fluid Rayleigh-Bénard convection*

Extensive progress has been made in the past to study Rayleigh-Benard convection (RBC) and the inherent heat transport scaling in circular and square cross-sectional test cells of various aspect ratios. The internal flow pattern in these cross-sectional geometries has been observed to be different, though the heat transport remains largely unaffected for low Prandtl number (Pr) fluid RBC. However, limited studies using high-Pr fluids have shown that the heat transport relationship can be influenced by manipulating side-wall boundary conditions. We use a new facility designed for interchangeable test cells to observe heat transport in high-Pr fluids for different cross-sectional geometries to better understand these differences. We present results at Rayleigh numbers up to 10⁹ for circular and square cross-sectional test cells with an aspect ratio 0.75, and using [O(10³)] Prandtl number working fluid.