Convection in an internally heated, high prandtl number fluid: A laboratory study

Publisher Website
Google Scholar
Abstract
The stability regimes for convection in an internally heated, high Prandtl number, glycerin-based solution have been investigated for the first time by inducing particular planforms under controlled conditions. Down hexagons were found to be stable to about 40 Rac having wavenumbers which are in reasonable agreement with both linear and finite amplitude calculations. Beyond this value of the Rayleigh number, the cells were observed to undergo a transition from flow down to flow up at the center. Most of these new cells are not completely closed and bear some similarity to distorted rolls. They were also found to be time dependent and their horizontal scale did not differ substantially from that associated with the hexagonal planform at lower Rayleigh numbers. However, at about 125 Rac , the onset of two-scale flow was observed—a phenomenon which may be associated with the finite thermal conductivity of the upper boundary.