Experiments on thermosolutal convection in a shallow rectangular enclosure

Natural convection of salt water solution due to combined horizontal temperature and concentration gradients in studies experimentally in a rectangular enclosure of aspect ratio 0.2. Both gradients are imposed in such a way that their effects are either cooperating or opposing. Flow visualization shows two types of global flow patterns in the enclosure—a unicell flow pattern and a multilayer flow pattern—and the latter is observed to appear in a certain range of Ra T -Ra S plane. Formation and growth of a layered flow structure with time is observed and described. More layers appear in the case of opposing thermal and solutal buoyancy forces than the cooperating case. Due to the double-diffusive nature of heat and salt, interesting temperature and concentration profiles are obtained in the multilayer flow regime.