Convection in ternary porous layers with depth-dependent permeability and viscosity

摘要

The onset of convection in horizontal porous layers with depth-dependent permeability and viscosity, heated from below and salted from above and below, is investigated. It is shown that the linear instability captures the physics of the problem. The thermal critical Rayleigh number, in closed form, is obtained. Applications to the earth's mantle and to how, in new artificial porous materials, the porosity should be stratified in order to significantly promote or delay heat transfer, are furnished.