An analytical study on both the Darcian and non-Darcian natural convection heat and mass transfer from point and horizontal line sources in saturated porous medium is reported in this paper. Convective flows are promoted by the density variation due to joint action of temperature and concentration gradients across plumes. Two mechanisms of diffusion, namely, molecular diffusion and hydrodynamic dispersion are characteristic for transport phenomena in porous media. Detailed scale analysis of coupled heat and mass transfer from a point or a horizontal line source in an infinite saturated porous medium is used to determine control parameters and scales of the plume transport characteristics from the governing equations in accordance with the relative contribution of the molecular diffusion and dispersion. Conservation equations are shown to have the closed-form solutions for the limiting cases of predominant manifestation whether molecular or hydrodynamic dispersion when L_e=l or the characteristic scales of the mixing lengths for heat and mass transfer are the same. Closed-form solutions are presented for the Darcy and non-Darcy natural convection for both point and line sources.
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