TH2M: Switch to constant solid volume fraction
Currently the solid volume fraction is variable depending on the solution. For current projects it is sufficient if the solid volume fraction is constant. Not all benchmarks are affected by the change.
In future the solid volume fraction could become an MPL model similarly to the PorosityFromMassBalance used in RM.
- Feature description was added to the changelog
- Tests covering your feature were added?
- Any new feature or behavior change was documented?