Abstract
The double diffusive natural convection of smoke in a horizontal main flow was numerically studied at the Prandtl number Pr=0.71, the Lewis number Le=5, the buoyancy ratio N=1, the Rayleigh number Ra=10^7 to 10^9 and the Peclet number Pe=Re-Pr=500 to 4000. Double diffusive phenomena occurred downstream with upward and downward plumes. When the Peclet number is small, the smoke was extensively disordered downstream. Then the smoke was bifurcated into an ascending and two descending plumes. An ascending plume developed at the center of smoke owing to the thermal buoyancy and two descending plumes developed with drops at the right-and-left sides of smoke owing to the solutal buoyancy.
