solvers::functions: Apply maxDeltaT from functions

The functions module now applies time-step restrictions from the
functions that are running, rather than from the sub-solver. The
sub-solver only exists to be constructed so that its data is available
to the functions. It should not affect the solution process in any way.

applications/modules/functions/functions.C

@@ -100,7 +100,7 @@ Foam::solvers::functions::~functions()
 
 Foam::scalar Foam::solvers::functions::maxDeltaT() const
 {
-    return solverPtr->maxDeltaT();
+    return vGreat;
 }
 
 

src/finiteVolume/functionObjects/fvModelFunctionObject/fvModelFunctionObject.C

@@ -78,4 +78,10 @@ bool Foam::functionObjects::fvModel::write()
 }
 
 
+Foam::scalar Foam::functionObjects::fvModel::maxDeltaT() const
+{
+    return fvModelPtr_().maxDeltaT();
+}
+
+
 // ************************************************************************* //

src/finiteVolume/functionObjects/fvModelFunctionObject/fvModelFunctionObject.H

@@ -124,6 +124,9 @@ public:
         //- Do nothing
         virtual bool write();
 
+        //- Return the maximum time-step for stable operation
+        virtual scalar maxDeltaT() const;
+
 
     // Member Operators