Natural convection heat transfer in fluid-saturated porous media has received much attention
during the past decades. This attention has been supported by many engineering applications, for
example, heat exchange between soil and atmosphere, high performance insulation for buildings,
chemical catalytic reactors, food processing, electrochemistry, metallurgy, grain storage, cooling of
radioactive waste containers, and compacted beds for the chemical industry. Porous media are also
of interest in relation to the underground spread of pollutants, solar power collectors, and geothermal
energy systems