Natural convection with discontinuous wall-temperature variations

At present, solutions for natural convection problems involving discontinuous changes in wall temperature do not exist. This paper reports results of an extensive experimental investigation of the particular case of a vertical flat plate with a step-change in wall temperature. Temperature profiles and local heat transfer coefficients determined with a Mach-Zehnder Interferometer are presented for a wide range of the pertinent parameters. The flow field associated with this problem was studied by means of a series of Tellurium dye experiments in water. Photographs are presented showing representative flow patterns, and the stability of the flow is considered as a function of the ratio of the excess temperature below a discontinuity to the excess temperature above.