Effect of thermal stratification on double-diffusive natural convection in a vertical porous enclosure

A numerical study on combined heat and mass transfer by natural convection adjacent to a vertical surface in a thermally stratified fluid saturated square porous enclosure is reported. The Galerkin finite element method on a graded grid system has been employed in the numerical computations. When thermal and species diffusion coefficients are equal, increasing levels of thermal stratification significantly influence both the aiding and opposing flow structures and their concomitant temperature fields. For unequal species and thermal diffusion coefficients changes in the concentration field structure are seen to be more prominent. The Nusselt (Nu) and Sherwood (Sh) number data have been presented for various values of Lewis number (Le), buoyancy ratio (B), and Rayleigh number (Ra) at various levels of stratification (S).