Double-diffusive Convection in a Two Layered Aqueous Solution by Lateral Heating and Cooling

Double-diffusive convection in a solutally stratified fluid destabilized by lateral heating and cooling two-layer was studied experimentally. In the range of initial buoyancy ratio N0=0.54-7.17, details of double-diffusive phenomena were investigated by visualization of temperature and flow fields using encapsulated liquid crystals and polystyrene particles. On starting the experiment, roll cell convection of two layer was formed by double-diffusion of heat and solute, and the interface broke after thermally quasi-steady state. Attention was focused on the undulation of the interface which occurred before interface breaks. The detailed structure and occurrence condition of undulation were elucidated. It is found that the time when the mixing of the two layer starts is determined by the buoyancy ratio N0 though it changed largely by experimental conditions. buoyancy ratio, double-diffusion, natural convection, secondary flow, visualization.