On the layered structure in a stable solute gradient heated from below

When a linear stable solute gradient, contained in a tall tank, is heated uniformly from below, double diffusive layers may be formed successively from the bottom to the top of the fluid. A simple model is developed which considers the evolution of the bottom mixed layer, and a set of experiments was performed when the temperature at the solid boundary is specified. The model and the experiments show that the instantaneous thickness of the bottom mixed layer is directly proportional to the difference between the instantaneous temperature of the solid boundary and that of the far fluid, and inversely proportional to the ambient solute gradient. The experiments reveal that during its formation the second layer persists above the bottom one notwithstanding the advancing interface below. Similar behavior is observed during the formation of subsequent secondary layers.