An experimental study of the coupled thermal boundary layers adjacent to a partition in a differentially heated cavity

The coupled thermal boundary layers adjacent to a vertical partition placed in the middle of a differentially heated cavity are experimentally investigated using the shadowgraph technique over the range of Rayleigh numbers from 2.6 × 109 to 1011. The cavity is filled with water and a temperature difference between the two sidewalls of the partitioned cavity is imposed. The experimental visualisation shows that the coupled thermal boundary layers are unsteady in the fully developed stage if the Rayleigh number is sufficiently high (e.g. Ra > 1010). The properties of the instability in the coupled thermal boundary layers adjacent to the partition are described and the dependence of these properties on the Rayleigh number is quantified.