A Study on Mixing Mechanism of a Stably Stratified Solution between the Heated and Cooled Vertical Parallel Plates. 2nd Report: On the Evolution of Layering and the Mechanism of Degradation of Layers.

In this report the evolution of layering and the mechanism of degradation of layers formed from a stably stratified solution between the heated and cooled vertical parallel plates are precisely discussed. The relationship between Ra, f which expresses the dimensionless parameter of temperature fluctuation in the layer and Ra, w which is related to the intensity of the natural convection flow induced by the heated and cooled walls is obtained. When Ra, w is less than 15000, Ra, f increases with the increase of Ra, w and the flow is laminar. When Ra, w is between 15000 and 25000, Ra, f increases rapidly with the increase of Ra, w and the transition to turbulence occurs. The analysis shows that the temperature fluctuation in the layer is attenuated due to the transfer of heat across the interfaces contacting with upper and lower layers and the horizontal convection flow disappears when the critical value of Ra, w is 16800.