On the structure of the flow due to the collision of opposed, vertical, free convection, boundary layers

Preliminary experimental results are reported for the structure of the flow due to the collision of a pair of boundary layers driven towards each other by buoyant forces along a vertical wall. Of the possible parameters characterizing the flow, a Rayleigh number ratio, R, and a dimensionless temperature difference, eta, emerge as important. When R is greater than 0.6 and less than 2.0: if eta is less than 20, the approaching streams merge in a two-dimensional streamlined manner; if eta is greater than 0.20 'fingering' of fluid between the streams and cross-stream secondary flows occur.