The Effect of Heterogeneity on the Onset of Double-Diffusive Convection Induced by Internal Heating in a Porous Medium: A Layered Model

In this paper we have investigated the effects of both weak and strong heterogeneity on the onset of double-diffusive convection which is induced by combined effects of internal heating and solutal gradient. To make analytical progress, we considered a composite porous medium consisting of two horizontal layers. We investigated the effects of heterogeneities in permeability, thermal conductivity, volumetric heat source strength, and porosity. The solutal diffusivity, which becomes effective when a vertical salinity gradient is imposed, is affected by variation of porosity. We found that the effect of solutal diffusivity is stabilizing when the porosity increases upwards.