From 0f4c6572bc2fe4ab3ab802e425eafb48dbf4dbbd Mon Sep 17 00:00:00 2001
From: Andrew Heather <>
Date: Thu, 27 Sep 2018 12:46:48 +0100
Subject: [PATCH] ENH: polyPatch - added areaFraction method

Helper function to calculate the current face area vs the area returned
from the current point locations.  Useful for ACMI-type baffles where we
scale the face areas without moving points.
---
 .../polyPatches/polyPatch/polyPatch.C         | 19 +++++++++++++++++++
 .../polyPatches/polyPatch/polyPatch.H         |  4 ++++
 2 files changed, 23 insertions(+)

diff --git a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
index d48d7e30ca..324203cf26 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
@@ -330,6 +330,25 @@ Foam::tmp<Foam::vectorField> Foam::polyPatch::faceCellCentres() const
 }
 
 
+Foam::tmp<Foam::scalarField> Foam::polyPatch::areaFraction() const
+{
+    tmp<scalarField> tfraction(new scalarField(size()));
+    scalarField& fraction = tfraction.ref();
+
+    const vectorField::subField faceAreas = this->faceAreas();
+    const pointField& points = this->points();
+
+    forAll(*this, facei)
+    {
+        const face& curFace = this->operator[](facei);
+        fraction[facei] =
+            mag(faceAreas[facei])/(curFace.mag(points) + ROOTVSMALL);
+    }
+
+    return tfraction;
+}
+
+
 const Foam::labelUList& Foam::polyPatch::faceCells() const
 {
     if (!faceCellsPtr_)
diff --git a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H
index a43c9e9844..0a185878d4 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H
@@ -372,6 +372,10 @@ public:
             //- Return face cell centres
             tmp<vectorField> faceCellCentres() const;
 
+            //- Return the area fraction as the ratio of the stored face area
+            //- and the area given by the face points
+            tmp<scalarField> areaFraction() const;
+
 
         // Addressing into mesh