Robustness improvement for layer addition/removal triggering

src/dynamicMesh/dynamicMesh/polyMeshModifiers/layerAdditionRemoval/addCellLayer.C

@@ -87,7 +87,7 @@ void Foam::layerAdditionRemoval::addCellLayer
         {
             extrusionDir[mpI] = points[ptc[mpI]] - points[mp[mpI]];
         }
-        extrusionDir *= addDelta_*maxLayerThickness_;
+        extrusionDir *= addDelta_()*maxLayerThickness_;
     }
     else
     {
@@ -118,7 +118,7 @@ void Foam::layerAdditionRemoval::addCellLayer
                 polyAddPoint
                 (
                     points[mp[pointI]]                  // point
-//                   + addDelta_*maxLayerThickness_*extrusionDir[pointI],
+//                   + addDelta_()*maxLayerThickness_*extrusionDir[pointI],
                   + extrusionDir[pointI],
                     mp[pointI],                         // master point
                     -1,                                 // zone for point

src/dynamicMesh/dynamicMesh/polyMeshModifiers/layerAdditionRemoval/layerAdditionRemoval.C

@@ -48,8 +48,19 @@ namespace Foam
 }
 
 
-const Foam::scalar Foam::layerAdditionRemoval::addDelta_ = 0.3;
-const Foam::scalar Foam::layerAdditionRemoval::removeDelta_ = 0.1;
+const Foam::debug::tolerancesSwitch
+Foam::layerAdditionRemoval::motionDelta_
+(
+    "layerAdditionRemoval::motionDelta",
+    0.01
+);
+
+const Foam::debug::tolerancesSwitch
+Foam::layerAdditionRemoval::addDelta_
+(
+    "layerAdditionRemoval::addDelta",
+    0.3
+);
 
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
@@ -354,7 +365,12 @@ bool Foam::layerAdditionRemoval::changeTopology() const
 
         topologicalChange = false;
     }
-    else if (avgDelta < oldLayerThickness_)
+    // New criterion to avoid round-off triggering layer addition/removal
+    // HJ, 30/Mar/2018
+    else if
+    (
+        (oldLayerThickness_ - avgDelta) > motionDelta_()*minLayerThickness_
+    )
     {
         // Layers moving towards removal
         if (minDelta < minLayerThickness_)
@@ -397,7 +413,12 @@ bool Foam::layerAdditionRemoval::changeTopology() const
             oldLayerThickness_ = avgDelta;
         }
     }
-    else
+    // New criterion to avoid round-off triggering layer addition/removal
+    // HJ, 30/Mar/2018
+    else if
+    (
+        (avgDelta - oldLayerThickness_) > motionDelta_()*minLayerThickness_
+    )
     {
         // Layers moving towards addition
         if (maxDelta > maxLayerThickness_)
@@ -422,6 +443,8 @@ bool Foam::layerAdditionRemoval::changeTopology() const
             oldLayerThickness_ = avgDelta;
         }
     }
+    // else the motion change is smaller than the tolerance and the layer
+    // interface is practically static.  HJ, 30/Mar/2018
 
     return topologicalChange;
 }

src/dynamicMesh/dynamicMesh/polyMeshModifiers/layerAdditionRemoval/layerAdditionRemoval.H

@@ -40,6 +40,7 @@ SourceFiles
 #include "polyMeshModifier.H"
 #include "primitiveFacePatch.H"
 #include "ZoneIDs.H"
+#include "tolerancesSwitch.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -128,13 +129,14 @@ class layerAdditionRemoval
 
     // Static data members
 
-        //- Thickness insertion fraction for the pre-motion
-        static const scalar addDelta_;
+        //- Motion detection fraction: if the motion is smaller than
+        // motionDelta*minLayerThickness_, it is assumed that the mesh is
+        // not layering
+        static const debug::tolerancesSwitch motionDelta_;
+
+        //- Thickness insertion fraction for the pre-motion
+        static const debug::tolerancesSwitch addDelta_;
 
-        //- Thickness removal fraction for the cell collapse
-        //  Note: the cell will be collapsed to this relative
-        //  thickness before the layer is removed.
-        static const scalar removeDelta_;
 
 public:
 
@@ -166,9 +168,8 @@ public:
         );
 
 
-    // Destructor
-
-        virtual ~layerAdditionRemoval();
+    //- Destructor
+    virtual ~layerAdditionRemoval();
 
 
     // Member Functions