Abstract
A two-layer, salt-stratified system destabilized and mixed by lateral heating and cooling is considered. We focus our attention on the quasi-steady process before the mixing process and study the structure of a diffusive interface separating the two convective cells, under various experimental conditions. The laser induced fluorescence technique exhibits that three dimensional time-periodic plumes travel along the upper and lower parts of the interface in a reverse sense, respectively and they are aligned in the spanwise direction with a constant spacing, which induces to the fluctuations of the temperature and species concentration. It is found that the dimensionless period of oscillation is inversely proportional to the 0.5 power of the thermal Rayleigh number, which is supported by a simple diffusion model within the interface.
