Abstract
The double diffusive natural convection arises owing to the rate difference between thermal and solutal diffusions in a fluid containing temperature and concentration gradients. The double diffusive layered convection due to thermal plume in linear concentration gradient system was numerically studied at the Prandtl number Pr=6, the Rayleigh number Ra=10^7 or 10^8, the Lewis number Le=100, and the buoyancy ratio N=1.5. Thermal plumes occur from the heat source on the bottom but stop the ascending owing to the concentration gradient. Then the plumes develop to the primary convection layer with time. The temperature in the primary convection layer increases with time, and second thermal plumes occur on the primary hot convection layer. Finally the second thermal plumes develop a secondary convection layer.
