constrainPressure: Updated to use the more efficient patch-based MRF::relative function

src/finiteVolume/cfdTools/general/constrainPressure/constrainPressure.C

@@ -43,51 +43,38 @@ void Foam::constrainPressure
 )
 {
     const fvMesh& mesh = p.mesh();
+
     volScalarField::GeometricBoundaryField& pBf = p.boundaryField();
 
-    bool hasFixedFluxBCs = false;
-    forAll(pBf, patchi)
-    {
-        if (isA<fixedFluxPressureFvPatchScalarField>(pBf[patchi]))
-        {
-            hasFixedFluxBCs = true;
-            break;
-        }
-    }
-
-    if (hasFixedFluxBCs)
-    {
+    const volVectorField::GeometricBoundaryField& UBf = U.boundaryField();
     const surfaceScalarField::GeometricBoundaryField& phiHbyABf =
         phiHbyA.boundaryField();
     const typename RAUType::GeometricBoundaryField& rhorAUBf =
         rhorAU.boundaryField();
+    const surfaceVectorField::GeometricBoundaryField& SfBf =
+        mesh.Sf().boundaryField();
     const surfaceScalarField::GeometricBoundaryField& magSfBf =
         mesh.magSf().boundaryField();
 
-        // Pre-compute tho relative flux for all patches: currently MRFZone does
-        // not support computing the relative flux for individual patches
-        FieldField<fvsPatchField, scalar> phiRelBf
-        (
-            MRF.relative(mesh.Sf().boundaryField() & U.boundaryField())
-        );
-
     forAll(pBf, patchi)
     {
         if (isA<fixedFluxPressureFvPatchScalarField>(pBf[patchi]))
         {
-                refCast<fixedFluxPressureFvPatchScalarField>(pBf[patchi])
-               .updateCoeffs
+            refCast<fixedFluxPressureFvPatchScalarField>
+            (
+                pBf[patchi]
+            ).updateCoeffs
             (
                 (
                     phiHbyABf[patchi]
-                      - rho.boundaryField()[patchi]*phiRelBf[patchi]
+                  - rho.boundaryField()[patchi]
+                   *MRF.relative(SfBf[patchi] & UBf[patchi], patchi)
                 )
                /(magSfBf[patchi]*rhorAUBf[patchi])
             );
         }
     }
 }
-}
 
 
 template<class RAUType>

src/finiteVolume/cfdTools/general/constrainPressure/constrainPressure.H

@@ -68,6 +68,13 @@ public:
         {
             return U;
         }
+
+        //- Return the argument unchanged
+        template<class Type>
+        inline const Type& relative(const Type& U, const label patchi) const
+        {
+            return U;
+        }
 };