From bf9b9204c31b472f936039de5e25c9a1eaeedfbb Mon Sep 17 00:00:00 2001
From: Andrew Heather <>
Date: Mon, 3 Jun 2024 10:46:27 +0100
Subject: [PATCH] ENH: MRF - added function to return the frame absolute flux

---
 .../cfdTools/general/MRF/MRFZoneList.C        | 23 ++++++++++++++++++-
 .../cfdTools/general/MRF/MRFZoneList.H        |  5 +++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.C b/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.C
index a66957b9ec..d50d8a65cf 100644
--- a/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.C
+++ b/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2017 OpenFOAM Foundation
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -28,6 +28,7 @@ License
 
 #include "MRFZoneList.H"
 #include "volFields.H"
+#include "surfaceFields.H"
 #include "fixedValueFvsPatchFields.H"
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
@@ -216,6 +217,26 @@ Foam::tmp<Foam::volVectorField> Foam::MRFZoneList::DDt
 }
 
 
+Foam::tmp<Foam::surfaceScalarField> Foam::MRFZoneList::phi() const
+{
+    auto tphi = surfaceScalarField::New
+    (
+        "phiMRF",
+        IOobject::NO_REGISTER,
+        mesh_,
+        dimensionedScalar(dimVelocity*dimArea, Zero)
+    );
+    auto& phi = tphi.ref();
+
+    for (const auto& mrf : *this)
+    {
+        mrf.makeAbsolute(phi);
+    }
+
+    return tphi;
+}
+
+
 void Foam::MRFZoneList::makeRelative(volVectorField& U) const
 {
     for (const auto& mrf: *this)
diff --git a/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.H b/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.H
index 72ee1c9860..c91c24f4e7 100644
--- a/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.H
+++ b/src/finiteVolume/cfdTools/general/MRF/MRFZoneList.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2018 OpenFOAM Foundation
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -127,6 +127,9 @@ public:
             const volVectorField& U
         ) const;
 
+        //- Return the MRF absolute flux
+        tmp<surfaceScalarField> phi() const;
+
         //- Make the given absolute velocity relative within the MRF region
         void makeRelative(volVectorField& U) const;