[implicit 2p2c] add possibility to choose between using a

ConstraintSolver or explicit calculation of secondary variables

For some problem settings, an explicit calculation of the secondary
variables proves to be more stable than using a ConstraintSolver. This
introduces the possiblity to choose between the two variants analogous
to 3p3c.

Reviewed by Bernd.


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@14119 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/implicit/2p2c/2p2cproperties.hh

@@ -69,6 +69,8 @@ NEW_PROP_TAG(EffectiveDiffusivityModel); //!< The employed model for the computa
 
 NEW_PROP_TAG(ProblemEnableGravity); //!< Returns whether gravity is considered in the problem
 NEW_PROP_TAG(UseMoles); //!< Defines whether mole (true) or mass (false) fractions are used
+NEW_PROP_TAG(UseConstraintSolver); //!< Determines whether the constraint solver should be used 
+
 NEW_PROP_TAG(ImplicitMassUpwindWeight); //!< The value of the upwind weight for the mass conservation equations
 NEW_PROP_TAG(ImplicitMobilityUpwindWeight); //!< Weight for the upwind mobility in the velocity calculation
 NEW_PROP_TAG(ReplaceCompEqIdx); //!< The index of the total mass balance equation,

dumux/implicit/2p2c/2p2cpropertydefaults.hh

@@ -160,6 +160,9 @@ SET_BOOL_PROP(TwoPTwoC, ProblemEnableGravity, true);
 //! Use mole fractions in the balance equations by default
 SET_BOOL_PROP(TwoPTwoC, UseMoles, true);
 
+//! Determines whether the constraint solver is used 
+SET_BOOL_PROP(TwoPTwoC, UseConstraintSolver, true);
+
 //! Set default value for the Forchheimer coefficient
 // Source: Ward, J.C. 1964 Turbulent flow in porous media. ASCE J. Hydraul. Div 90.
 //        Actually the Forchheimer coefficient is also a function of the dimensions of the