diff --git a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.C b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.C
index 7fbfb02724..57945b0246 100644
--- a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.C
+++ b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.C
@@ -66,6 +66,31 @@ bool Foam::functionObjects::fvMeshFunctionObject::writeField
 }
 
 
+bool Foam::functionObjects::fvMeshFunctionObject::clearField
+(
+    const word& fieldName
+)
+{
+    if (foundField<regIOobject>(fieldName))
+    {
+        const regIOobject& resultField = lookupField<regIOobject>(fieldName);
+
+        if (resultField.ownedByRegistry())
+        {
+            return const_cast<regIOobject&>(resultField).checkOut();
+        }
+        else
+        {
+            return false;
+        }
+    }
+    else
+    {
+        return true;
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::fvMeshFunctionObject::fvMeshFunctionObject
diff --git a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.H b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.H
index 62315000f7..78c259f0f7 100644
--- a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.H
+++ b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObject.H
@@ -95,6 +95,9 @@ protected:
         //- Write field if present in objectRegistry
         bool writeField(const word& fieldName);
 
+        //- Clear field from the objectRegistry if present
+        bool clearField(const word& fieldName);
+
 
 private:
 
diff --git a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObjectTemplates.C b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObjectTemplates.C
index 48b680620e..b3e07b2513 100644
--- a/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObjectTemplates.C
+++ b/src/finiteVolume/fvMesh/fvMeshFunctionObject/fvMeshFunctionObjectTemplates.C
@@ -74,10 +74,22 @@ bool Foam::functionObjects::fvMeshFunctionObject::store
      && mesh_.foundObject<FieldType>(fieldName)
     )
     {
-        const_cast<FieldType&>
+        const FieldType& field =
         (
             mesh_.lookupObject<FieldType>(fieldName)
-        ) = tfield;
+        );
+
+        // If there is a result field already registered assign to the new
+        // result field otherwise transfer ownership of the new result field to
+        // the object registry
+        if (&field != &tfield())
+        {
+            const_cast<FieldType&>(field) = tfield;
+        }
+        else
+        {
+            mesh_.objectRegistry::store(tfield.ptr());
+        }
     }
     else
     {
diff --git a/src/postProcessing/functionObjects/field/CourantNo/CourantNo.C b/src/postProcessing/functionObjects/field/CourantNo/CourantNo.C
index 736fdece67..53cd86a606 100644
--- a/src/postProcessing/functionObjects/field/CourantNo/CourantNo.C
+++ b/src/postProcessing/functionObjects/field/CourantNo/CourantNo.C
@@ -66,41 +66,7 @@ Foam::functionObjects::CourantNo::byRho
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
-
-Foam::functionObjects::CourantNo::CourantNo
-(
-    const word& name,
-    const Time& runTime,
-    const dictionary& dict
-)
-:
-    fieldExpression(name, runTime, dict, "phi", "Co")
-{
-    read(dict);
-}
-
-
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::functionObjects::CourantNo::~CourantNo()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::CourantNo::read(const dictionary& dict)
-{
-    fieldExpression::read(dict);
-
-    phiName_ = dict.lookupOrDefault<word>("phi", "phi");
-    rhoName_ = dict.lookupOrDefault<word>("rho", "rho");
-
-    return true;
-}
-
-
-bool Foam::functionObjects::CourantNo::execute(const bool postProcess)
+bool Foam::functionObjects::CourantNo::calc()
 {
     if (foundField<surfaceScalarField>(phiName_))
     {
@@ -163,4 +129,38 @@ bool Foam::functionObjects::CourantNo::execute(const bool postProcess)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::CourantNo::CourantNo
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "phi", "Co")
+{
+    read(dict);
+}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::CourantNo::~CourantNo()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+bool Foam::functionObjects::CourantNo::read(const dictionary& dict)
+{
+    fieldExpression::read(dict);
+
+    phiName_ = dict.lookupOrDefault<word>("phi", "phi");
+    rhoName_ = dict.lookupOrDefault<word>("rho", "rho");
+
+    return true;
+}
+
+
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/CourantNo/CourantNo.H b/src/postProcessing/functionObjects/field/CourantNo/CourantNo.H
index d29afdf24d..346cd2bb7e 100644
--- a/src/postProcessing/functionObjects/field/CourantNo/CourantNo.H
+++ b/src/postProcessing/functionObjects/field/CourantNo/CourantNo.H
@@ -73,12 +73,15 @@ class CourantNo
 
     // Private Member Functions
 
-        //- Divide Co by rho if required
+        //- Divide the Courant number by rho if required
         tmp<volScalarField::Internal> byRho
         (
             const tmp<volScalarField::Internal>& Co
         ) const;
 
+        //- Calculate the Courant number field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -105,9 +108,6 @@ public:
 
         //- Read the CourantNo data
         virtual bool read(const dictionary&);
-
-        //- Calculate the Courant number
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/Lambda2/Lambda2.C b/src/postProcessing/functionObjects/field/Lambda2/Lambda2.C
index e6f8ccfad1..0023147876 100644
--- a/src/postProcessing/functionObjects/field/Lambda2/Lambda2.C
+++ b/src/postProcessing/functionObjects/field/Lambda2/Lambda2.C
@@ -45,28 +45,9 @@ namespace functionObjects
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-Foam::functionObjects::Lambda2::Lambda2
-(
-    const word& name,
-    const Time& runTime,
-    const dictionary& dict
-)
-:
-    fieldExpression(name, runTime, dict, "U", "Lambda2")
-{}
-
-
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::functionObjects::Lambda2::~Lambda2()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::Lambda2::execute(const bool postProcess)
+bool Foam::functionObjects::Lambda2::calc()
 {
     if (foundField<volVectorField>(fieldName_))
     {
@@ -93,4 +74,23 @@ bool Foam::functionObjects::Lambda2::execute(const bool postProcess)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::Lambda2::Lambda2
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "U", "Lambda2")
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::Lambda2::~Lambda2()
+{}
+
+
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/Lambda2/Lambda2.H b/src/postProcessing/functionObjects/field/Lambda2/Lambda2.H
index 34cc98d73c..f94e6cd1d7 100644
--- a/src/postProcessing/functionObjects/field/Lambda2/Lambda2.H
+++ b/src/postProcessing/functionObjects/field/Lambda2/Lambda2.H
@@ -61,6 +61,11 @@ class Lambda2
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the Lambda2 field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -81,12 +86,6 @@ public:
 
     //- Destructor
     virtual ~Lambda2();
-
-
-    // Member Functions
-
-        //- Calculate the Lambda2 field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/MachNo/MachNo.C b/src/postProcessing/functionObjects/field/MachNo/MachNo.C
index d252a45b30..1d08a64025 100644
--- a/src/postProcessing/functionObjects/field/MachNo/MachNo.C
+++ b/src/postProcessing/functionObjects/field/MachNo/MachNo.C
@@ -45,28 +45,9 @@ namespace functionObjects
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-Foam::functionObjects::MachNo::MachNo
-(
-    const word& name,
-    const Time& runTime,
-    const dictionary& dict
-)
-:
-    fieldExpression(name, runTime, dict, "U", "Ma")
-{}
-
-
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::functionObjects::MachNo::~MachNo()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::MachNo::execute(const bool postProcess)
+bool Foam::functionObjects::MachNo::calc()
 {
     if
     (
@@ -92,4 +73,23 @@ bool Foam::functionObjects::MachNo::execute(const bool postProcess)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::MachNo::MachNo
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "U", "Ma")
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::MachNo::~MachNo()
+{}
+
+
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/MachNo/MachNo.H b/src/postProcessing/functionObjects/field/MachNo/MachNo.H
index 4d744f6219..342647cd90 100644
--- a/src/postProcessing/functionObjects/field/MachNo/MachNo.H
+++ b/src/postProcessing/functionObjects/field/MachNo/MachNo.H
@@ -60,6 +60,11 @@ class MachNo
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the Mach number field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -81,12 +86,6 @@ public:
 
     //- Destructor
     virtual ~MachNo();
-
-
-    // Member Functions
-
-        //- Calculate the Mach number field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/PecletNo/PecletNo.C b/src/postProcessing/functionObjects/field/PecletNo/PecletNo.C
index 2164947a98..5e11a10ee4 100644
--- a/src/postProcessing/functionObjects/field/PecletNo/PecletNo.C
+++ b/src/postProcessing/functionObjects/field/PecletNo/PecletNo.C
@@ -46,6 +46,41 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::PecletNo::calc()
+{
+    if (foundField<surfaceScalarField>(phiName_))
+    {
+        tmp<volScalarField> nuEff
+        (
+            mesh_.lookupObject<turbulenceModel>
+            (
+                turbulenceModel::propertiesName
+            ).nuEff()
+        );
+
+        const surfaceScalarField& phi =
+            mesh_.lookupObject<surfaceScalarField>(phiName_);
+
+        return store
+        (
+            resultName_,
+            mag(phi)
+           /(
+                mesh_.magSf()
+               *mesh_.surfaceInterpolation::deltaCoeffs()
+               *fvc::interpolate(nuEff)
+            )
+        );
+    }
+    else
+    {
+        return false;
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::PecletNo::PecletNo
@@ -79,37 +114,4 @@ bool Foam::functionObjects::PecletNo::read(const dictionary& dict)
 }
 
 
-bool Foam::functionObjects::PecletNo::execute(const bool postProcess)
-{
-    if (foundField<surfaceScalarField>(phiName_))
-    {
-        tmp<volScalarField> nuEff
-        (
-            mesh_.lookupObject<turbulenceModel>
-            (
-                turbulenceModel::propertiesName
-            ).nuEff()
-        );
-
-        const surfaceScalarField& phi =
-            mesh_.lookupObject<surfaceScalarField>(phiName_);
-
-        return store
-        (
-            resultName_,
-            mag(phi)
-           /(
-                mesh_.magSf()
-               *mesh_.surfaceInterpolation::deltaCoeffs()
-               *fvc::interpolate(nuEff)
-            )
-        );
-    }
-    else
-    {
-        return false;
-    }
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/PecletNo/PecletNo.H b/src/postProcessing/functionObjects/field/PecletNo/PecletNo.H
index 7dd7149f76..3ff90f0cd4 100644
--- a/src/postProcessing/functionObjects/field/PecletNo/PecletNo.H
+++ b/src/postProcessing/functionObjects/field/PecletNo/PecletNo.H
@@ -66,6 +66,12 @@ class PecletNo
         word phiName_;
 
 
+    // Private Member Functions
+
+        //- Calculate the Peclet number field and return true if successful
+        virtual bool calc();
+
+
 public:
 
     //- Runtime type information
@@ -92,9 +98,6 @@ public:
 
         //- Read the PecletNo data
         virtual bool read(const dictionary&);
-
-        //- Calculate the Peclet number field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/Q/Q.C b/src/postProcessing/functionObjects/field/Q/Q.C
index 52cc9f1489..043550caa6 100644
--- a/src/postProcessing/functionObjects/field/Q/Q.C
+++ b/src/postProcessing/functionObjects/field/Q/Q.C
@@ -45,28 +45,9 @@ namespace functionObjects
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-Foam::functionObjects::Q::Q
-(
-    const word& name,
-    const Time& runTime,
-    const dictionary& dict
-)
-:
-    fieldExpression(name, runTime, dict, "U", "Q")
-{}
-
-
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::functionObjects::Q::~Q()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::Q::execute(const bool postProcess)
+bool Foam::functionObjects::Q::calc()
 {
     if (foundField<volVectorField>(fieldName_))
     {
@@ -87,4 +68,23 @@ bool Foam::functionObjects::Q::execute(const bool postProcess)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::Q::Q
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "U", "Q")
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::Q::~Q()
+{}
+
+
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/Q/Q.H b/src/postProcessing/functionObjects/field/Q/Q.H
index feca1d1b4c..1305b02b1f 100644
--- a/src/postProcessing/functionObjects/field/Q/Q.H
+++ b/src/postProcessing/functionObjects/field/Q/Q.H
@@ -64,6 +64,11 @@ class Q
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the Q field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -84,12 +89,6 @@ public:
 
     //- Destructor
     virtual ~Q();
-
-
-    // Member Functions
-
-        //- Calculate the Q field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.C b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.C
index 50a055c0a6..60cc2d36f7 100644
--- a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.C
+++ b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.C
@@ -38,6 +38,25 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::blendingFactor::calc()
+{
+    bool processed = false;
+
+    processed = processed || calcBF<scalar>();
+    processed = processed || calcBF<vector>();
+
+    if (!processed)
+    {
+        WarningInFunction
+            << "Unprocessed field " << fieldName_ << endl;
+    }
+
+    return processed;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::blendingFactor::blendingFactor
@@ -73,21 +92,4 @@ bool Foam::functionObjects::blendingFactor::read(const dictionary& dict)
 }
 
 
-bool Foam::functionObjects::blendingFactor::execute(const bool postProcess)
-{
-    bool processed = false;
-
-    processed = processed || calc<scalar>();
-    processed = processed || calc<vector>();
-
-    if (!processed)
-    {
-        WarningInFunction
-            << "Unprocessed field " << fieldName_ << endl;
-    }
-
-    return processed;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.H b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.H
index b7f0363be2..56f0310f7f 100644
--- a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.H
+++ b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactor.H
@@ -69,9 +69,12 @@ class blendingFactor
 
     // Private Member Functions
 
-        //- Calculate the blending factor
+        //- Calculate the blending factor field
         template<class Type>
-        bool calc();
+        bool calcBF();
+
+        //- Calculate the blending factor field and return true if successful
+        virtual bool calc();
 
 
 public:
@@ -99,9 +102,6 @@ public:
 
         //- Read the blendingFactor data
         virtual bool read(const dictionary&);
-
-        //- Calculate the blending-factor
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactorTemplates.C b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactorTemplates.C
index 565b77c0d7..6c51490edb 100644
--- a/src/postProcessing/functionObjects/field/blendingFactor/blendingFactorTemplates.C
+++ b/src/postProcessing/functionObjects/field/blendingFactor/blendingFactorTemplates.C
@@ -30,7 +30,7 @@ License
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::functionObjects::blendingFactor::calc()
+bool Foam::functionObjects::blendingFactor::calcBF()
 {
     typedef GeometricField<Type, fvPatchField, volMesh> FieldType;
 
diff --git a/src/postProcessing/functionObjects/field/div/div.C b/src/postProcessing/functionObjects/field/div/div.C
index c8aefb1693..582e33ef55 100644
--- a/src/postProcessing/functionObjects/field/div/div.C
+++ b/src/postProcessing/functionObjects/field/div/div.C
@@ -40,6 +40,19 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::div::calc()
+{
+    bool processed = false;
+
+    processed = processed || calcDiv<surfaceScalarField>();
+    processed = processed || calcDiv<volVectorField>();
+
+    return processed;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::div::div
@@ -59,23 +72,4 @@ Foam::functionObjects::div::~div()
 {}
 
 
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::div::execute(const bool postProcess)
-{
-    bool processed = false;
-
-    processed = processed || calc<surfaceScalarField>();
-    processed = processed || calc<volVectorField>();
-
-    if (!processed)
-    {
-        WarningInFunction
-            << "Unprocessed field " << fieldName_ << endl;
-    }
-
-    return processed;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/div/div.H b/src/postProcessing/functionObjects/field/div/div.H
index 1076300b88..778147454f 100644
--- a/src/postProcessing/functionObjects/field/div/div.H
+++ b/src/postProcessing/functionObjects/field/div/div.H
@@ -66,7 +66,10 @@ class div
         //- Calculate the divergence of either a
         //  volScalarField or a surfaceScalarField and register the result
         template<class FieldType>
-        bool calc();
+        bool calcDiv();
+
+        //- Calculate the divergence field and return true if successful
+        virtual bool calc();
 
 
 public:
@@ -88,12 +91,6 @@ public:
 
     //- Destructor
     virtual ~div();
-
-
-    // Member Functions
-
-        //- Calculate the divergence field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/div/divTemplates.C b/src/postProcessing/functionObjects/field/div/divTemplates.C
index e791e25b2c..fb204a4569 100644
--- a/src/postProcessing/functionObjects/field/div/divTemplates.C
+++ b/src/postProcessing/functionObjects/field/div/divTemplates.C
@@ -28,7 +28,7 @@ License
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class FieldType>
-bool Foam::functionObjects::div::calc()
+bool Foam::functionObjects::div::calcDiv()
 {
     if (foundField<FieldType>(fieldName_))
     {
diff --git a/src/postProcessing/functionObjects/field/enstrophy/enstrophy.C b/src/postProcessing/functionObjects/field/enstrophy/enstrophy.C
index 3c28af5147..9370c668c9 100644
--- a/src/postProcessing/functionObjects/field/enstrophy/enstrophy.C
+++ b/src/postProcessing/functionObjects/field/enstrophy/enstrophy.C
@@ -45,6 +45,27 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::enstrophy::calc()
+{
+    if (foundField<volVectorField>(fieldName_))
+    {
+        return store
+        (
+            resultName_,
+            0.5*magSqr(fvc::curl(lookupField<volVectorField>(fieldName_)))
+        );
+    }
+    else
+    {
+        return false;
+    }
+
+    return true;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::enstrophy::enstrophy
@@ -64,25 +85,4 @@ Foam::functionObjects::enstrophy::~enstrophy()
 {}
 
 
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::enstrophy::execute(const bool postProcess)
-{
-    if (foundField<volVectorField>(fieldName_))
-    {
-        return store
-        (
-            resultName_,
-            0.5*magSqr(fvc::curl(lookupField<volVectorField>(fieldName_)))
-        );
-    }
-    else
-    {
-        return false;
-    }
-
-    return true;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/enstrophy/enstrophy.H b/src/postProcessing/functionObjects/field/enstrophy/enstrophy.H
index 211102e20a..ae044e8aac 100644
--- a/src/postProcessing/functionObjects/field/enstrophy/enstrophy.H
+++ b/src/postProcessing/functionObjects/field/enstrophy/enstrophy.H
@@ -59,6 +59,11 @@ class enstrophy
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the enstrophy field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -79,12 +84,6 @@ public:
 
     //- Destructor
     virtual ~enstrophy();
-
-
-    // Member Functions
-
-        //- Calculate the enstrophy field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.C b/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.C
index f4d5575594..868e0d78f5 100644
--- a/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.C
+++ b/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.C
@@ -36,6 +36,15 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * //
+
+bool Foam::functionObjects::fieldExpression::calc()
+{
+    NotImplemented;
+    return false;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::fieldExpression::fieldExpression
@@ -81,9 +90,35 @@ bool Foam::functionObjects::fieldExpression::read(const dictionary& dict)
 }
 
 
+bool Foam::functionObjects::fieldExpression::execute(const bool postProcess)
+{
+    if (!calc())
+    {
+        Warning
+            << "functionObject " << type() << ": Cannot find required field "
+            << fieldName_ << endl;
+
+        // Clear the result field from the objectRegistry if present
+        clear();
+
+        return false;
+    }
+    else
+    {
+        return true;
+    }
+}
+
+
 bool Foam::functionObjects::fieldExpression::write(const bool postProcess)
 {
-    return fvMeshFunctionObject::writeField(resultName_);
+    return writeField(resultName_);
+}
+
+
+bool Foam::functionObjects::fieldExpression::clear()
+{
+    return clearField(resultName_);
 }
 
 
diff --git a/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.H b/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.H
index 3b0e645e23..f6c7eb227f 100644
--- a/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.H
+++ b/src/postProcessing/functionObjects/field/fieldExpression/fieldExpression.H
@@ -69,6 +69,11 @@ protected:
         word resultName_;
 
 
+    // Protected member functions
+
+        virtual bool calc();
+
+
 private:
 
     // Private Member Functions
@@ -109,10 +114,13 @@ public:
         virtual bool read(const dictionary&);
 
         //- Calculate the fieldExpressionergence field
-        virtual bool execute(const bool postProcess = false) = 0;
+        virtual bool execute(const bool postProcess = false);
 
         //- Write the fieldExpressionergence field
         virtual bool write(const bool postProcess = false);
+
+        //- Clear the result field from the objectRegistry
+        virtual bool clear();
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/flowType/flowType.C b/src/postProcessing/functionObjects/field/flowType/flowType.C
index d282617778..5193f3736c 100644
--- a/src/postProcessing/functionObjects/field/flowType/flowType.C
+++ b/src/postProcessing/functionObjects/field/flowType/flowType.C
@@ -45,28 +45,9 @@ namespace functionObjects
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-Foam::functionObjects::flowType::flowType
-(
-    const word& name,
-    const Time& runTime,
-    const dictionary& dict
-)
-:
-    fieldExpression(name, runTime, dict, "U", "flowType")
-{}
-
-
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::functionObjects::flowType::~flowType()
-{}
-
-
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::flowType::execute(const bool postProcess)
+bool Foam::functionObjects::flowType::calc()
 {
     if (foundField<volVectorField>(fieldName_))
     {
@@ -97,4 +78,23 @@ bool Foam::functionObjects::flowType::execute(const bool postProcess)
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::flowType::flowType
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "U", "flowType")
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::flowType::~flowType()
+{}
+
+
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/flowType/flowType.H b/src/postProcessing/functionObjects/field/flowType/flowType.H
index f73e82b732..54205736f4 100644
--- a/src/postProcessing/functionObjects/field/flowType/flowType.H
+++ b/src/postProcessing/functionObjects/field/flowType/flowType.H
@@ -70,6 +70,11 @@ class flowType
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the flowType field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -90,12 +95,6 @@ public:
 
     //- Destructor
     virtual ~flowType();
-
-
-    // Member Functions
-
-        //- Calculate the flowType field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/grad/grad.C b/src/postProcessing/functionObjects/field/grad/grad.C
index 1ee5d82f8c..b265ec80b7 100644
--- a/src/postProcessing/functionObjects/field/grad/grad.C
+++ b/src/postProcessing/functionObjects/field/grad/grad.C
@@ -38,6 +38,19 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::grad::calc()
+{
+    bool processed = false;
+
+    processed = processed || calcGrad<scalar>();
+    processed = processed || calcGrad<vector>();
+
+    return processed;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::grad::grad
@@ -59,23 +72,4 @@ Foam::functionObjects::grad::~grad()
 {}
 
 
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::grad::execute(const bool postProcess)
-{
-    bool processed = false;
-
-    processed = processed || calc<scalar>();
-    processed = processed || calc<vector>();
-
-    if (!processed)
-    {
-        WarningInFunction
-            << "Unprocessed field " << fieldName_ << endl;
-    }
-
-    return true;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/grad/grad.H b/src/postProcessing/functionObjects/field/grad/grad.H
index 68bd4450f6..36db751f31 100644
--- a/src/postProcessing/functionObjects/field/grad/grad.H
+++ b/src/postProcessing/functionObjects/field/grad/grad.H
@@ -64,7 +64,10 @@ class grad
 
         //- Calculate the magnitude of the field and register the result
         template<class Type>
-        bool calc();
+        bool calcGrad();
+
+        //- Calculate the gradient field and return true if successful
+        virtual bool calc();
 
 
 public:
@@ -86,12 +89,6 @@ public:
 
     //- Destructor
     virtual ~grad();
-
-
-    // Member Functions
-
-        //- Calculate the gradient field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/grad/gradTemplates.C b/src/postProcessing/functionObjects/field/grad/gradTemplates.C
index 026b1a3c70..1eeae18466 100644
--- a/src/postProcessing/functionObjects/field/grad/gradTemplates.C
+++ b/src/postProcessing/functionObjects/field/grad/gradTemplates.C
@@ -28,7 +28,7 @@ License
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::functionObjects::grad::calc()
+bool Foam::functionObjects::grad::calcGrad()
 {
     typedef GeometricField<Type, fvPatchField, volMesh> VolFieldType;
     typedef GeometricField<Type, fvsPatchField, surfaceMesh> SurfaceFieldType;
diff --git a/src/postProcessing/functionObjects/field/mag/mag.C b/src/postProcessing/functionObjects/field/mag/mag.C
index c2e519d267..b37a053c58 100644
--- a/src/postProcessing/functionObjects/field/mag/mag.C
+++ b/src/postProcessing/functionObjects/field/mag/mag.C
@@ -38,6 +38,28 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::mag::calc()
+{
+    bool processed = false;
+
+    processed = processed || calcMag<scalar>();
+    processed = processed || calcMag<vector>();
+    processed = processed || calcMag<sphericalTensor>();
+    processed = processed || calcMag<symmTensor>();
+    processed = processed || calcMag<tensor>();
+
+    if (!processed)
+    {
+        WarningInFunction
+            << "Unprocessed field " << fieldName_ << endl;
+    }
+
+    return processed;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::mag::mag
@@ -59,26 +81,4 @@ Foam::functionObjects::mag::~mag()
 {}
 
 
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::mag::execute(const bool postProcess)
-{
-    bool processed = false;
-
-    processed = processed || calc<scalar>();
-    processed = processed || calc<vector>();
-    processed = processed || calc<sphericalTensor>();
-    processed = processed || calc<symmTensor>();
-    processed = processed || calc<tensor>();
-
-    if (!processed)
-    {
-        WarningInFunction
-            << "Unprocessed field " << fieldName_ << endl;
-    }
-
-    return processed;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/mag/mag.H b/src/postProcessing/functionObjects/field/mag/mag.H
index a77951827e..f27908762d 100644
--- a/src/postProcessing/functionObjects/field/mag/mag.H
+++ b/src/postProcessing/functionObjects/field/mag/mag.H
@@ -64,7 +64,10 @@ class mag
 
         //- Calculate the magnitude of the field and register the result
         template<class Type>
-        bool calc();
+        bool calcMag();
+
+        //- Calculate the magnitude of the field and return true if successful
+        virtual bool calc();
 
 
 public:
@@ -86,12 +89,6 @@ public:
 
     //- Destructor
     virtual ~mag();
-
-
-    // Member Functions
-
-        //- Calculate the magnitude field
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/mag/magTemplates.C b/src/postProcessing/functionObjects/field/mag/magTemplates.C
index 5b78efb93a..8cb4debaa6 100644
--- a/src/postProcessing/functionObjects/field/mag/magTemplates.C
+++ b/src/postProcessing/functionObjects/field/mag/magTemplates.C
@@ -29,7 +29,7 @@ License
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::functionObjects::mag::calc()
+bool Foam::functionObjects::mag::calcMag()
 {
     typedef GeometricField<Type, fvPatchField, volMesh> VolFieldType;
     typedef GeometricField<Type, fvsPatchField, surfaceMesh> SurfaceFieldType;
diff --git a/src/postProcessing/functionObjects/field/pressure/pressure.C b/src/postProcessing/functionObjects/field/pressure/pressure.C
index da8a326931..d2f854f181 100644
--- a/src/postProcessing/functionObjects/field/pressure/pressure.C
+++ b/src/postProcessing/functionObjects/field/pressure/pressure.C
@@ -159,6 +159,27 @@ Foam::functionObjects::pressure::coeff
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::pressure::calc()
+{
+    if (foundField<volScalarField>(fieldName_))
+    {
+        const volScalarField& p = lookupField<volScalarField>(fieldName_);
+
+        return store
+        (
+            resultName_,
+            coeff(pRef(pDyn(p, rhoScale(p))))
+        );
+    }
+    else
+    {
+        return false;
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::pressure::pressure
@@ -238,23 +259,4 @@ bool Foam::functionObjects::pressure::read(const dictionary& dict)
 }
 
 
-bool Foam::functionObjects::pressure::execute(const bool postProcess)
-{
-    if (foundField<volScalarField>(fieldName_))
-    {
-        const volScalarField& p = lookupField<volScalarField>(fieldName_);
-
-        return store
-        (
-            resultName_,
-            coeff(pRef(pDyn(p, rhoScale(p))))
-        );
-    }
-    else
-    {
-        return false;
-    }
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/pressure/pressure.H b/src/postProcessing/functionObjects/field/pressure/pressure.H
index bd92001723..4970c5aa58 100644
--- a/src/postProcessing/functionObjects/field/pressure/pressure.H
+++ b/src/postProcessing/functionObjects/field/pressure/pressure.H
@@ -196,6 +196,9 @@ class pressure
         //- Convert to coeff by applying the freestream dynamic pressure scaling
         tmp<volScalarField> coeff(const tmp<volScalarField>& tp) const;
 
+        //- Calculate the derived pressure field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -222,9 +225,6 @@ public:
 
         //- Read the pressure data
         virtual bool read(const dictionary&);
-
-        //- Calculate the selected pressure form
-        virtual bool execute(const bool postProcess = false);
 };
 
 
diff --git a/src/postProcessing/functionObjects/field/vorticity/vorticity.C b/src/postProcessing/functionObjects/field/vorticity/vorticity.C
index 8c2291136f..b6c462e50f 100644
--- a/src/postProcessing/functionObjects/field/vorticity/vorticity.C
+++ b/src/postProcessing/functionObjects/field/vorticity/vorticity.C
@@ -45,6 +45,27 @@ namespace functionObjects
 }
 
 
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::vorticity::calc()
+{
+    if (foundField<volVectorField>(fieldName_))
+    {
+        return store
+        (
+            resultName_,
+            fvc::curl(lookupField<volVectorField>(fieldName_))
+        );
+    }
+    else
+    {
+        return false;
+    }
+
+    return true;
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::vorticity::vorticity
@@ -64,25 +85,4 @@ Foam::functionObjects::vorticity::~vorticity()
 {}
 
 
-// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
-
-bool Foam::functionObjects::vorticity::execute(const bool postProcess)
-{
-    if (foundField<volVectorField>(fieldName_))
-    {
-        return store
-        (
-            resultName_,
-            fvc::curl(lookupField<volVectorField>(fieldName_))
-        );
-    }
-    else
-    {
-        return false;
-    }
-
-    return true;
-}
-
-
 // ************************************************************************* //
diff --git a/src/postProcessing/functionObjects/field/vorticity/vorticity.H b/src/postProcessing/functionObjects/field/vorticity/vorticity.H
index 13c1f096f6..44a0b10163 100644
--- a/src/postProcessing/functionObjects/field/vorticity/vorticity.H
+++ b/src/postProcessing/functionObjects/field/vorticity/vorticity.H
@@ -59,6 +59,11 @@ class vorticity
 :
     public fieldExpression
 {
+    // Private Member Functions
+
+        //- Calculate the vorticity field and return true if successful
+        virtual bool calc();
+
 
 public:
 
@@ -79,12 +84,6 @@ public:
 
     //- Destructor
     virtual ~vorticity();
-
-
-    // Member Functions
-
-        //- Calculate the vorticity field
-        virtual bool execute(const bool postProcess = false);
 };