NUMERICAL-SIMULATION AND HOLOGRAPHIC VISUALIZATION OF DOUBLE DIFFUSIVE CONVECTION IN A HORIZONTAL CONCENTRIC ANNULUS

The time-dependent double diffusive convection in a horizontal concentric annulus is investigated both by numerical analysis and by holographic interferometry. In order to calculate stream functions, temperature-, concentration- and density-fields, the finite difference technique is utilized. Inner and outer cylinders of the annulus are kept isotherm, with the inner cylinder heated. The annulus is filled with an H2O-NaCl solution, which is isothermal initially and submitted to a linear and stable stratification of the solution. The results reveal a considerable decrease in heat transfer as compared to natural convection without a stabilizing salt gradient. In addition experiments are performed on double diffusive convection about a vertical cylinder in a square container.