Dispersed phase discretization - Mixture Model, Laminar Flow

Hi all,

I have a question related to the discretization of the dispersed phase in the Mixture Model, Laminar Flow interface. Under "Discretization" is only possible to choose the discretization for the fluid phase, while for the solid phase (i.e. phid) is not.

Do you know which discretization is used for the solid phase? Is it linear?

Any idea on why it is not possible to choose the discretization for the solid phase?

Thanks,

J