Dynamic heat transfer in a tall annulus: Effects of the porous matrix for low Darcy numbers

This work focuses on the transient natural convection in vertical annuli partially filled with a porous medium, characterized by a low value of Darcy number. The generalized porous medium model has been implemented and solved by using a validated and stable version of a fully explicit fractional step algorithm. Sensitivity analyses are performed here by changing both the geometrical features of the cavity and the porous domain, both the properties of the porous medium. The results are compared with those obtained for the same cavity in absence of the porous insert, in order to investigate how it influences the transient evolution of the Nusselt number.