fvcMeshPhi: added 'relative' equivalent of absolute function

src/finiteVolume/finiteVolume/fvc/fvcMeshPhi.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2013 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2014 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -148,6 +148,41 @@ void Foam::fvc::makeAbsolute
 }
 
 
+Foam::tmp<Foam::surfaceScalarField> Foam::fvc::relative
+(
+    const tmp<surfaceScalarField>& tphi,
+    const volVectorField& U
+)
+{
+    if (tphi().mesh().moving())
+    {
+        return tphi - fvc::meshPhi(U);
+    }
+    else
+    {
+        return tmp<surfaceScalarField>(tphi, true);
+    }
+}
+
+
+Foam::tmp<Foam::surfaceScalarField> Foam::fvc::relative
+(
+    const tmp<surfaceScalarField>& tphi,
+    const volScalarField& rho,
+    const volVectorField& U
+)
+{
+    if (tphi().mesh().moving())
+    {
+        return tphi - fvc::interpolate(rho)*fvc::meshPhi(rho, U);
+    }
+    else
+    {
+        return tmp<surfaceScalarField>(tphi, true);
+    }
+}
+
+
 Foam::tmp<Foam::surfaceScalarField> Foam::fvc::absolute
 (
     const tmp<surfaceScalarField>& tphi,

src/finiteVolume/finiteVolume/fvc/fvcMeshPhi.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2012 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2014 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -33,7 +33,6 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-
 #ifndef fvcMeshPhi_H
 #define fvcMeshPhi_H
 
@@ -118,6 +117,22 @@ namespace fvc
     );
 
 
+    //- Return the given absolute flux in relative form
+    tmp<surfaceScalarField> relative
+    (
+        const tmp<surfaceScalarField>& tphi,
+        const volVectorField& U
+    );
+
+    //- Return the given absolute flux in relative form
+    tmp<surfaceScalarField> relative
+    (
+        const tmp<surfaceScalarField>& tphi,
+        const volScalarField& rho,
+        const volVectorField& U
+    );
+
+
     //- Return the given relative flux in absolute form
     tmp<surfaceScalarField> absolute
     (