From 056bb4f0a0354d45d14423de1f0266d3d89a8bf9 Mon Sep 17 00:00:00 2001
From: Mattijs Janssens <ext-mjanssens@esi-group.com>
Date: Thu, 30 May 2024 15:15:56 +0000
Subject: [PATCH] FaceCellWave: travel through coupled ACMI. See #3139

---
 .../polyPatches/polyPatch/polyPatch.C         | 18 ++++++-
 .../polyPatches/polyPatch/polyPatch.H         | 16 ++++--
 ...ureForceBaffleVelocityFvPatchVectorField.C | 30 +++++++++++-
 .../wallDistAddressing/wallDistAddressing.C   | 37 +++++++++-----
 .../inverseDistanceDiffusivity.C              |  1 -
 .../inverseVolume/inverseVolumeDiffusivity.C  |  1 -
 .../basic/InteractionLists/InteractionLists.C |  6 +--
 .../cyclicACMIPolyPatch/cyclicACMIPolyPatch.C | 29 +++++++++--
 .../algorithms/MeshWave/FaceCellWave.C        | 11 ++++-
 src/meshTools/cellDist/cellDistFuncs.C        | 49 +++++++++++++++----
 .../cellDist/patchWave/patchDataWave.C        | 44 ++++++++++-------
 .../cellDist/patchWave/patchDataWave.H        |  4 +-
 src/meshTools/cellDist/patchWave/patchWave.C  | 48 +++++++++---------
 src/meshTools/cellDist/patchWave/patchWave.H  |  4 +-
 14 files changed, 212 insertions(+), 86 deletions(-)

diff --git a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
index 3f2530d6da..bc132c24ab 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.C
@@ -350,13 +350,15 @@ Foam::tmp<Foam::vectorField> Foam::polyPatch::faceCellCentres() const
 }
 
 
-Foam::tmp<Foam::scalarField> Foam::polyPatch::areaFraction() const
+Foam::tmp<Foam::scalarField> Foam::polyPatch::areaFraction
+(
+    const pointField& points
+) const
 {
     auto tfraction = tmp<scalarField>::New(size());
     auto& fraction = tfraction.ref();
 
     const vectorField::subField faceAreas = this->faceAreas();
-    const pointField& points = this->points();
 
     forAll(*this, facei)
     {
@@ -369,6 +371,18 @@ Foam::tmp<Foam::scalarField> Foam::polyPatch::areaFraction() const
 }
 
 
+const Foam::tmp<Foam::scalarField>& Foam::polyPatch::areaFraction() const
+{
+    return areaFraction_;
+}
+
+
+void Foam::polyPatch::areaFraction(const tmp<scalarField>& fraction)
+{
+    areaFraction_ = fraction;
+}
+
+
 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 c676179197..49d2786bc0 100644
--- a/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H
+++ b/src/OpenFOAM/meshes/polyMesh/polyPatches/polyPatch/polyPatch.H
@@ -88,6 +88,9 @@ class polyPatch
         //- Demand-driven: global edge addressing
         mutable std::unique_ptr<labelList> mePtr_;
 
+        //- Cached area fraction
+        tmp<scalarField> areaFraction_;
+
 
 protected:
 
@@ -441,9 +444,16 @@ 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;
+            //- Calculate the area fraction as the ratio of the stored face
+            //  area and the area given by the face points.
+            tmp<scalarField> areaFraction(const pointField& points) const;
+
+            //- Return the cached area fraction. Usually only set for the
+            //- non-overlap patches on ACMI.
+            const tmp<scalarField>& areaFraction() const;
+
+            //- Set cached area fraction
+            void areaFraction(const tmp<scalarField>&);
 
 
         // Addressing into mesh
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
index 6f2a989768..cb80bf364a 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
@@ -342,6 +342,7 @@ void Foam::activePressureForceBaffleVelocityFvPatchVectorField::updateCoeffs()
             ).neighbFvPatch().Sf();
         }
 
+
         // Update this wall patch
         vectorField::subField Sfw = patch().patch().faceAreas();
         vectorField newSfw((1 - areaFraction)*initWallSf_);
@@ -350,16 +351,41 @@ void Foam::activePressureForceBaffleVelocityFvPatchVectorField::updateCoeffs()
             Sfw[facei] = newSfw[facei];
         }
         const_cast<scalarField&>(patch().magSf()) = mag(patch().Sf());
+        // Cache fraction
+        const_cast<polyPatch&>(patch().patch()).areaFraction
+        (
+            tmp<scalarField>::New
+            (
+                patch().patch().size(),
+                (1-areaFraction)
+            )
+        );
+
 
         // Update owner side of cyclic
         const_cast<vectorField&>(cyclicPatch.Sf()) = areaFraction*initCyclicSf_;
-
         const_cast<scalarField&>(cyclicPatch.magSf()) = mag(cyclicPatch.Sf());
+        const_cast<polyPatch&>(cyclicPatch.patch()).areaFraction
+        (
+            tmp<scalarField>::New
+            (
+                cyclicPatch.patch().size(),
+                areaFraction
+            )
+        );
+
 
         // Update neighbour side of cyclic
         const_cast<vectorField&>(nbrPatch.Sf()) = areaFraction*nbrCyclicSf_;
-
         const_cast<scalarField&>(nbrPatch.magSf()) = mag(nbrPatch.Sf());
+        const_cast<polyPatch&>(cyclicPatch.patch()).areaFraction
+        (
+            tmp<scalarField>::New
+            (
+                nbrPatch.patch().size(),
+                areaFraction
+            )
+        );
 
         curTimeIndex_ = this->db().time().timeIndex();
     }
diff --git a/src/finiteVolume/fvMesh/wallDist/wallDistAddressing/wallDistAddressing.C b/src/finiteVolume/fvMesh/wallDist/wallDistAddressing/wallDistAddressing.C
index 653079e98e..67a20853af 100644
--- a/src/finiteVolume/fvMesh/wallDist/wallDistAddressing/wallDistAddressing.C
+++ b/src/finiteVolume/fvMesh/wallDist/wallDistAddressing/wallDistAddressing.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2023 OpenCFD Ltd.
+    Copyright (C) 2023-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -146,29 +146,40 @@ void Foam::wallDistAddressing::correct(volScalarField& y)
     globalWallsPtr_.reset(new globalIndex(nWalls));
     const globalIndex& globalWalls = globalWallsPtr_();
 
-    labelList seedFaces(nWalls);
-    List<wallPointAddressing> seedInfo(nWalls);
+    DynamicList<label> seedFaces(nWalls);
+    DynamicList<wallPointAddressing> seedInfo(nWalls);
 
 
     nWalls = 0;
     for (const label patchi : patchIDs_)
     {
         const auto& fc = C.boundaryField()[patchi];
+        const auto& areaFraction = fc.patch().patch().areaFraction();
 
         forAll(fc, patchFacei)
         {
-            seedFaces[nWalls] = fc.patch().start()+patchFacei;
-            seedInfo[nWalls] = wallPointAddressing
+            if
             (
-                fc[patchFacei],
-                gt.encode
+                !areaFraction
+             || (areaFraction()[patchFacei] > 0.5)    // mostly wall
+            )
+            {
+                seedFaces.append(fc.patch().start()+patchFacei);
+                seedInfo.append
                 (
-                    Pstream::myProcNo(),
-                    nWalls,
-                    gt.nullTransformIndex()
-                ),
-                scalar(0.0)
-            );
+                    wallPointAddressing
+                    (
+                        fc[patchFacei],
+                        gt.encode
+                        (
+                            Pstream::myProcNo(),
+                            nWalls,
+                            gt.nullTransformIndex()
+                        ),
+                        scalar(0.0)
+                    )
+                );
+            }
             nWalls++;
         }
     }
diff --git a/src/fvMotionSolver/motionDiffusivity/inverseDistance/inverseDistanceDiffusivity.C b/src/fvMotionSolver/motionDiffusivity/inverseDistance/inverseDistanceDiffusivity.C
index f023d3c46a..6eea2f7675 100644
--- a/src/fvMotionSolver/motionDiffusivity/inverseDistance/inverseDistanceDiffusivity.C
+++ b/src/fvMotionSolver/motionDiffusivity/inverseDistance/inverseDistanceDiffusivity.C
@@ -28,7 +28,6 @@ License
 
 #include "inverseDistanceDiffusivity.H"
 #include "addToRunTimeSelectionTable.H"
-#include "patchWave.H"
 #include "HashSet.H"
 #include "surfaceInterpolate.H"
 #include "zeroGradientFvPatchFields.H"
diff --git a/src/fvMotionSolver/motionDiffusivity/inverseVolume/inverseVolumeDiffusivity.C b/src/fvMotionSolver/motionDiffusivity/inverseVolume/inverseVolumeDiffusivity.C
index ff0582a84e..49a6c7694f 100644
--- a/src/fvMotionSolver/motionDiffusivity/inverseVolume/inverseVolumeDiffusivity.C
+++ b/src/fvMotionSolver/motionDiffusivity/inverseVolume/inverseVolumeDiffusivity.C
@@ -27,7 +27,6 @@ License
 
 #include "inverseVolumeDiffusivity.H"
 #include "addToRunTimeSelectionTable.H"
-#include "patchWave.H"
 #include "HashSet.H"
 #include "surfaceInterpolate.H"
 #include "zeroGradientFvPatchFields.H"
diff --git a/src/lagrangian/basic/InteractionLists/InteractionLists.C b/src/lagrangian/basic/InteractionLists/InteractionLists.C
index 8bbd96b67b..edae174aa4 100644
--- a/src/lagrangian/basic/InteractionLists/InteractionLists.C
+++ b/src/lagrangian/basic/InteractionLists/InteractionLists.C
@@ -299,11 +299,11 @@ void Foam::InteractionLists<ParticleType>::buildInteractionLists()
     {
         if (isA<wallPolyPatch>(patch))
         {
-            const scalarField areaFraction(patch.areaFraction());
+            const auto& areaFraction = patch.areaFraction();
 
-            forAll(areaFraction, facei)
+            forAll(patch, facei)
             {
-                if (areaFraction[facei] > 0.5)
+                if (!areaFraction || areaFraction()[facei] > 0.5)
                 {
                     localWallFaces.append(facei + patch.start());
                 }
diff --git a/src/meshTools/AMIInterpolation/patches/cyclicACMI/cyclicACMIPolyPatch/cyclicACMIPolyPatch.C b/src/meshTools/AMIInterpolation/patches/cyclicACMI/cyclicACMIPolyPatch/cyclicACMIPolyPatch.C
index 4a7452e93a..404f19f671 100644
--- a/src/meshTools/AMIInterpolation/patches/cyclicACMI/cyclicACMIPolyPatch/cyclicACMIPolyPatch.C
+++ b/src/meshTools/AMIInterpolation/patches/cyclicACMI/cyclicACMIPolyPatch/cyclicACMIPolyPatch.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2022,2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -217,10 +217,24 @@ void Foam::cyclicACMIPolyPatch::scalePatchFaceAreas
         return;
     }
 
-    forAll(noSf, facei)
     {
-        const scalar w = min(maxTol, max(tolerance_, mask[facei]));
-        noSf[facei] = noFaceArea[facei]*(scalar(1) - w);
+        tmp<scalarField> scale
+        (
+            scalar(1)
+          - min
+            (
+                max(mask, tolerance_),
+                maxTol
+            )
+        );
+
+        // Scale area
+        forAll(noSf, facei)
+        {
+            noSf[facei] = noFaceArea[facei]*scale()[facei];
+        }
+        // Cache scaling
+        const_cast<polyPatch&>(nonOverlapPatch).areaFraction(scale);
     }
 
     if (!createAMIFaces_)
@@ -235,10 +249,15 @@ void Foam::cyclicACMIPolyPatch::scalePatchFaceAreas
         // Scale the coupled patch face areas
         vectorField::subField Sf = acmipp.faceAreas();
 
+        tmp<scalarField> scale(max(tolerance_, mask));
+
+        // Scale area
         forAll(Sf, facei)
         {
-            Sf[facei] = faceArea[facei]*max(tolerance_, mask[facei]);
+            Sf[facei] = faceArea[facei]*scale()[facei];
         }
+        // Cache scaling
+        const_cast<cyclicACMIPolyPatch&>(acmipp).areaFraction(scale);
 
         // Re-normalise the weights since the effect of overlap is already
         // accounted for in the area
diff --git a/src/meshTools/algorithms/MeshWave/FaceCellWave.C b/src/meshTools/algorithms/MeshWave/FaceCellWave.C
index a5487c290a..b96792829b 100644
--- a/src/meshTools/algorithms/MeshWave/FaceCellWave.C
+++ b/src/meshTools/algorithms/MeshWave/FaceCellWave.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2023 OpenCFD Ltd.
+    Copyright (C) 2018-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -821,8 +821,17 @@ void Foam::FaceCellWave<Type, TrackingData>::handleAMICyclicPatches()
             }
 
             // Merge into global storage
+
+            const auto& areaFraction = patch.areaFraction();
+
             forAll(receiveInfo, i)
             {
+                if (areaFraction && areaFraction()[i] <= 0.5)
+                {
+                    // not coupled
+                    continue;
+                }
+
                 const label meshFacei = cycPatch.start()+i;
 
                 const Type& newInfo = receiveInfo[i];
diff --git a/src/meshTools/cellDist/cellDistFuncs.C b/src/meshTools/cellDist/cellDistFuncs.C
index 301354bc60..1b064dc391 100644
--- a/src/meshTools/cellDist/cellDistFuncs.C
+++ b/src/meshTools/cellDist/cellDistFuncs.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020,2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -235,6 +235,8 @@ void Foam::cellDistFuncs::correctBoundaryFaceCells
     Map<label>& nearestFace
 ) const
 {
+    const auto& pbm = mesh().boundaryMesh();
+
     // Size neighbours array for maximum possible (= size of largest patch)
     DynamicList<label> neighbours(maxPatchSize(patchIDs));
 
@@ -242,15 +244,22 @@ void Foam::cellDistFuncs::correctBoundaryFaceCells
     const vectorField& cellCentres = mesh().cellCentres();
     const labelList& faceOwner = mesh().faceOwner();
 
-    forAll(mesh().boundaryMesh(), patchi)
+    forAll(pbm, patchi)
     {
         if (patchIDs.found(patchi))
         {
-            const polyPatch& patch = mesh().boundaryMesh()[patchi];
+            const polyPatch& patch = pbm[patchi];
+            const auto& areaFraction = patch.areaFraction();
 
             // Check cells with face on wall
             forAll(patch, patchFacei)
             {
+                if (areaFraction && (areaFraction()[patchFacei] <= 0.5))
+                {
+                    // is mostly coupled
+                    continue;
+                }
+
                 getPointNeighbours(patch, patchFacei, neighbours);
 
                 label celli = faceOwner[patch.start() + patchFacei];
@@ -283,20 +292,42 @@ void Foam::cellDistFuncs::correctBoundaryPointCells
 {
     // Correct all (non-visited) cells with point on wall
 
+    const auto& pbm = mesh().boundaryMesh();
     const vectorField& cellCentres = mesh().cellCentres();
 
-    forAll(mesh().boundaryMesh(), patchi)
+    forAll(pbm, patchi)
     {
         if (patchIDs.found(patchi))
         {
-            const polyPatch& patch = mesh().boundaryMesh()[patchi];
-
+            const polyPatch& patch = pbm[patchi];
+            const auto& localFaces = patch.localFaces();
             const labelList& meshPoints = patch.meshPoints();
             const labelListList& pointFaces = patch.pointFaces();
 
-            forAll(meshPoints, meshPointi)
+            bitSet isWallPoint(meshPoints.size(), true);
             {
-                const label vertI = meshPoints[meshPointi];
+                const auto& areaFraction = patch.areaFraction();
+
+                // Check cells with face on wall
+                forAll(patch, patchFacei)
+                {
+                    if (!areaFraction || (areaFraction()[patchFacei] <= 0.5))
+                    {
+                        // face mostly coupled
+                        isWallPoint.unset(localFaces[patchFacei]);
+                    }
+                }
+            }
+
+
+            forAll(meshPoints, patchPointi)
+            {
+                const label vertI = meshPoints[patchPointi];
+
+                if (!isWallPoint[patchPointi])
+                {
+                    continue;
+                }
 
                 const labelList& neighbours = mesh().pointCells(vertI);
 
@@ -304,7 +335,7 @@ void Foam::cellDistFuncs::correctBoundaryPointCells
                 {
                     if (!nearestFace.found(celli))
                     {
-                        const labelList& wallFaces = pointFaces[meshPointi];
+                        const labelList& wallFaces = pointFaces[patchPointi];
 
                         label minFacei = -1;
 
diff --git a/src/meshTools/cellDist/patchWave/patchDataWave.C b/src/meshTools/cellDist/patchWave/patchDataWave.C
index dfa48df725..293018e8d9 100644
--- a/src/meshTools/cellDist/patchWave/patchDataWave.C
+++ b/src/meshTools/cellDist/patchWave/patchDataWave.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020,2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -41,37 +41,45 @@ template<class TransferType, class TrackingData>
 void Foam::patchDataWave<TransferType, TrackingData>::setChangedFaces
 (
     const labelHashSet& patchIDs,
-    labelList& changedFaces,
-    List<TransferType>& faceDist
+    DynamicList<label>& changedFaces,
+    DynamicList<TransferType>& faceDist
 ) const
 {
     const polyMesh& mesh = cellDistFuncs::mesh();
 
-    label nChangedFaces = 0;
-
     forAll(mesh.boundaryMesh(), patchi)
     {
         if (patchIDs.found(patchi))
         {
             const polyPatch& patch = mesh.boundaryMesh()[patchi];
 
+            const auto& areaFraction = patch.areaFraction();
+
+            const auto faceCentres(patch.faceCentres());
+
             const Field<Type>& patchField = initialPatchValuePtrs_[patchi];
 
-            forAll(patch.faceCentres(), patchFacei)
+            forAll(faceCentres, patchFacei)
             {
-                label meshFacei = patch.start() + patchFacei;
+                if
+                (
+                    !areaFraction
+                 || (areaFraction()[patchFacei] > 0.5)    // mostly wall
+                )
+                {
+                    label meshFacei = patch.start() + patchFacei;
+                    changedFaces.append(meshFacei);
 
-                changedFaces[nChangedFaces] = meshFacei;
-
-                faceDist[nChangedFaces] =
-                    TransferType
+                    faceDist.append
                     (
-                        patch.faceCentres()[patchFacei],
-                        patchField[patchFacei],
-                        0.0
+                        TransferType
+                        (
+                            faceCentres[patchFacei],
+                            patchField[patchFacei],
+                            0.0
+                        )
                     );
-
-                nChangedFaces++;
+                }
             }
         }
     }
@@ -222,8 +230,8 @@ void Foam::patchDataWave<TransferType, TrackingData>::correct()
     // Count walls
     label nWalls = sumPatchSize(patchIDs_);
 
-    List<TransferType> faceDist(nWalls);
-    labelList changedFaces(nWalls);
+    DynamicList<TransferType> faceDist(nWalls);
+    DynamicList<label> changedFaces(nWalls);
 
     setChangedFaces(patchIDs_, changedFaces, faceDist);
 
diff --git a/src/meshTools/cellDist/patchWave/patchDataWave.H b/src/meshTools/cellDist/patchWave/patchDataWave.H
index f7f79707e5..764efcd46b 100644
--- a/src/meshTools/cellDist/patchWave/patchDataWave.H
+++ b/src/meshTools/cellDist/patchWave/patchDataWave.H
@@ -115,8 +115,8 @@ private:
         void setChangedFaces
         (
             const labelHashSet& patchIDs,
-            labelList&,
-            List<TransferType>&
+            DynamicList<label>& changedFaces,
+            DynamicList<TransferType>& faceDist
         ) const;
 
         //- Copy MeshWave values into *this
diff --git a/src/meshTools/cellDist/patchWave/patchWave.C b/src/meshTools/cellDist/patchWave/patchWave.C
index 6f07859038..e8d583fb23 100644
--- a/src/meshTools/cellDist/patchWave/patchWave.C
+++ b/src/meshTools/cellDist/patchWave/patchWave.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
+    Copyright (C) 2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,50 +36,49 @@ License
 void Foam::patchWave::setChangedFaces
 (
     const labelHashSet& patchIDs,
-    labelList& changedFaces,
-    List<wallPoint>& faceDist
+    DynamicList<label>& changedFaces,
+    DynamicList<wallPoint>& faceDist
 ) const
 {
     const polyMesh& mesh = cellDistFuncs::mesh();
 
-    label nChangedFaces = 0;
-
     forAll(mesh.boundaryMesh(), patchi)
     {
         if (patchIDs.found(patchi))
         {
             const polyPatch& patch = mesh.boundaryMesh()[patchi];
 
-            forAll(patch.faceCentres(), patchFacei)
+            const auto& areaFraction = patch.areaFraction();
+
+            const auto faceCentres(patch.faceCentres());
+
+            forAll(faceCentres, patchFacei)
             {
-                label meshFacei = patch.start() + patchFacei;
-
-                changedFaces[nChangedFaces] = meshFacei;
-
-                faceDist[nChangedFaces] =
-                    wallPoint
-                    (
-                        patch.faceCentres()[patchFacei],
-                        0.0
-                    );
-
-                nChangedFaces++;
+                if
+                (
+                    !areaFraction
+                 || (areaFraction()[patchFacei] > 0.5)    // mostly wall
+                )
+                {
+                    changedFaces.append(patch.start() + patchFacei);
+                    faceDist.append(wallPoint(faceCentres[patchFacei], 0.0));
+                }
             }
         }
     }
 
     for (const label facei : sourceIDs_)
     {
-        changedFaces[nChangedFaces] = facei;
+        changedFaces.append(facei);
 
-        faceDist[nChangedFaces] =
+        faceDist.append
+        (
             wallPoint
             (
                 mesh.faceCentres()[facei],
                 0.0
-            );
-
-        nChangedFaces++;
+            )
+        );
     }
 }
 
@@ -181,8 +181,8 @@ void Foam::patchWave::correct()
 
     label nPatch = sumPatchSize(patchIDs_) + sourceIDs_.size();
 
-    List<wallPoint> faceDist(nPatch);
-    labelList changedFaces(nPatch);
+    DynamicList<wallPoint> faceDist(nPatch);
+    DynamicList<label> changedFaces(nPatch);
 
     // Set to faceDist information to facecentre on walls.
     setChangedFaces(patchIDs_, changedFaces, faceDist);
diff --git a/src/meshTools/cellDist/patchWave/patchWave.H b/src/meshTools/cellDist/patchWave/patchWave.H
index d7259d78a1..a99f05aa56 100644
--- a/src/meshTools/cellDist/patchWave/patchWave.H
+++ b/src/meshTools/cellDist/patchWave/patchWave.H
@@ -89,8 +89,8 @@ class patchWave
         void setChangedFaces
         (
             const labelHashSet& patchIDs,
-            labelList& changedFaces,
-            List<wallPoint>& changedInfo
+            DynamicList<label>& changedFaces,
+            DynamicList<wallPoint>& faceDist
         ) const;
 
         //- Copy MeshWave cell values. Return number of illegal/unset