BUG: inconsistent faceArea on processor boundaries (fixes #2683)

- was missing evaluateCoupled on the initial faceAreaNormals field
  (related to #2507)

ENH: simplify/consistent geometry updating

src/finiteArea/faMesh/faBoundaryMesh/faBoundaryMesh.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -185,12 +185,26 @@ Foam::faBoundaryMesh::faBoundaryMesh
 
 void Foam::faBoundaryMesh::calcGeometry()
 {
-    // processorFaPatch geometry triggers calculation of pointNormals.
+    // processor initGeometry send/recv the following:
+    //   - edgeCentres() : faMesh::edgeCentres()
+    //   - edgeLengths() : faMesh::Le()
+    //   - edgeFaceCentres() : faMesh::areaCentres()
+    //
+    // faMesh::Le() has its own point-to-point communication (OK) but
+    // triggers either/or edgeAreaNormals(), pointAreaNormals()
+    // with their own communication that can block.
+
     // This uses parallel comms and hence will not be trigggered
     // on processors that do not have a processorFaPatch so instead
     // force construction.
+
+    (void)mesh_.edgeAreaNormals();
     (void)mesh_.pointAreaNormals();
 
+    (void)mesh_.areaCentres();
+    (void)mesh_.faceAreaNormals();
+
+
     PstreamBuffers pBufs(Pstream::defaultCommsType);
 
     if
@@ -780,12 +794,15 @@ bool Foam::faBoundaryMesh::checkDefinition(const bool report) const
 
 void Foam::faBoundaryMesh::movePoints(const pointField& p)
 {
-    // processorFaPatch geometry triggers calculation of pointNormals.
-    // This uses parallel comms and hence will not be trigggered
-    // on processors that do not have a processorFaPatch so instead
-    // force construction.
+    // See comments in calcGeometry()
+
+    (void)mesh_.edgeAreaNormals();
     (void)mesh_.pointAreaNormals();
 
+    (void)mesh_.areaCentres();
+    (void)mesh_.faceAreaNormals();
+
+
     PstreamBuffers pBufs(Pstream::defaultCommsType);
 
     if

src/finiteArea/faMesh/faMesh.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
-    Copyright (C) 2020-2022 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -265,6 +265,27 @@ void Foam::faMesh::clearOut() const
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
+void Foam::faMesh::syncGeom()
+{
+    if (UPstream::parRun())
+    {
+        // areaCentres()
+        if (centresPtr_)
+        {
+            centresPtr_->boundaryFieldRef()
+                .evaluateCoupled<processorFaPatch>();
+        }
+
+        // faceAreaNormals()
+        if (faceAreaNormalsPtr_)
+        {
+            faceAreaNormalsPtr_->boundaryFieldRef()
+                .evaluateCoupled<processorFaPatch>();
+        }
+    }
+}
+
+
 bool Foam::faMesh::init(const bool doInit)
 {
     if (doInit)
@@ -284,18 +305,7 @@ bool Foam::faMesh::init(const bool doInit)
     // Calculate the geometry for the patches (transformation tensors etc.)
     boundary_.calcGeometry();
 
-    // Ensure processor/processor information is properly synchronised
-    if (Pstream::parRun())
-    {
-        const_cast<areaVectorField&>(areaCentres()).boundaryFieldRef()
-            .evaluateCoupled<processorFaPatch>();
-
-        // This roughly corresponds to what OpenFOAM-v2112 (and earlier) had,
-        // but should nominally be unnecessary.
-        //
-        /// const_cast<areaVectorField&>(faceAreaNormals()).boundaryFieldRef()
-        ///     .evaluateCoupled<processorFaPatch>();
-    }
+    syncGeom();
 
     return false;
 }
@@ -955,7 +965,6 @@ bool Foam::faMesh::movePoints()
 
     clearGeomNotAreas();
 
-    // To satisfy the motion interface for MeshObject, const cast is needed
     if (patchPtr_)
     {
         patchPtr_->movePoints(newPoints);
@@ -969,6 +978,8 @@ bool Foam::faMesh::movePoints()
 
     // Note: Fluxes were dummy?
 
+    syncGeom();
+
     return true;
 }
 

src/finiteArea/faMesh/faMesh.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
-    Copyright (C) 2021-2022 OpenCFD Ltd.
+    Copyright (C) 2021-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -599,6 +599,10 @@ public:
         //- Initialise non-demand-driven data etc
         bool init(const bool doInit);
 
+        //- Processor/processor synchronisation for geometry fields.
+        //  Largely internal use only (slightly hacky).
+        void syncGeom();
+
 
     // Database
 

src/finiteArea/faMesh/faMeshDemandDrivenData.C

@@ -603,6 +603,12 @@ void Foam::faMesh::calcAreaCentres() const
             }
         }
     }
+
+    // Parallel consistency, exchange on processor patches
+    if (UPstream::parRun())
+    {
+        centres.boundaryFieldRef().evaluateCoupled<processorFaPatch>();
+    }
 }
 
 
@@ -750,6 +756,12 @@ void Foam::faMesh::calcFaceAreaNormals() const
     {
         faceNormals.boundaryFieldRef()[patchI] = edgeNormalsBoundary[patchI];
     }
+
+    // Parallel consistency, exchange on processor patches
+    if (UPstream::parRun())
+    {
+        faceNormals.boundaryFieldRef().evaluateCoupled<processorFaPatch>();
+    }
 }
 
 

src/finiteArea/faMesh/faMeshTools/faMeshTools.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2012-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -61,6 +61,8 @@ void Foam::faMeshTools::forceDemandDriven(faMesh& mesh)
     (void)mesh.pointAreaNormals();
     (void)mesh.faceCurvatures();
     (void)mesh.edgeTransformTensors();
+
+    mesh.syncGeom();
 }