I want to define a source term in a porous region which is included in a domain (material is air). This domain is heated from the bottom, where the porous is located, so there is a temperature gradient between bottom and top of the domain. This source will be a function of the temperature difference between the temperature of the domain (space without the porous) and the temperature of the porous. Any ideas? Thanks

It seems that you are going to add only energy source term in the porous region. You have to know the amount of heat (Q) added to the porous zone in terms of Watts (J/s). Also I think that the porous region will have a number of cells. Then the source term in each of those cell will be (Q/total cell volume). But I do not know how you will get this Q value.

Hope this helps

Hiranya