The default Porosity εp of the solid matrix is taken
From material. The Porous Matrix node supports the use of a
Porous Material node, where the porosity is defined in the manner of
where θs,i and
θimf,i are the volume fractions given in
Solid and
Immobile Fluids subnodes under the
Porous Material node.
For User defined, enter a value or expression for the porosity.