The effect of thermal expansion on porous media convection. Part 2: Thermal convection solution

The impact of thermal expansion and the corresponding non-Boussinesq effect s on porous media convection are considered. The results show that the non- Boussinesq effects decouple from the rest, and solving the Boussinesq syste m separately is needed even when non-Boussinesq effects are being investiga ted. The thermal expansion is shown to have a lasting impact on the post-tr ansient convection only for values of Rayleigh number substantially beyond the convection threshold, where the amplitude of convection is not small. I n the neighbourhood of the convection threshold the thermal expansion has o nly a transient impact on the solution. It is also evident from the results that the neglect of the time derivative term in the extended Darcy equatio n might introduce a significant error when oscillatory effects are present.