Buoyancy ratio effects on coupled radiation and double-diffusive convection in non-gray air-H2O mixtures

In this paper we study the effect of the (mass-to-thermal) buoyancy ratio N on the interaction between gas radiation and double diffusive convection in a square cavity filled with a non-gray air-H₂O mixtures at constant average concentration of H₂O (13%). Uniform temperatures and concentrations are imposed along the vertical walls, while the horizontal walls are assumed to be adiabatic and impermeable to mass transfer. The governing equations are solved by a finite-difference method and the spectral dependency of gas radiative properties is handled by the SLW model of Denison and Webb. The results obtained, in opposing flow case, are graphically displayed for three value of N (-0.15, -0.95 and -1.91) to illustrate the influence of this parameter on concentration, temperature and velocity profiles as well as heat and mass flux. Non-gray results are also compared to gray solutions.