ENH: snappyHexMesh: rename switch from keepHex to mergePatchFaces

applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C

@@ -1431,12 +1431,16 @@ int main(int argc, char *argv[])
     const Switch wantSnap(meshDict.lookup("snap"));
     const Switch wantLayers(meshDict.lookup("addLayers"));
 
-    const Switch keepHex(meshDict.lookupOrDefault("keepHex", false));
+    const Switch mergePatchFaces
+    (
+        meshDict.lookupOrDefault("mergePatchFaces", true)
+    );
 
-    if (keepHex)
+    if (!mergePatchFaces)
     {
-        Info<< "Avoiding generating non-(split)hex cells." << nl
-            << endl;
+        Info<< "Not merging patch-faces of cell to preserve"
+            << " (split)hex cell shape."
+            << nl << endl;
     }
 
 
@@ -1466,7 +1470,7 @@ int main(int argc, char *argv[])
             refineParams,
             snapParams,
             refineParams.handleSnapProblems(),
-            keepHex,        // keepHex
+            mergePatchFaces,        // merge co-planar faces
             motionDict
         );
 
@@ -1506,7 +1510,7 @@ int main(int argc, char *argv[])
         (
             snapDict,
             motionDict,
-            !keepHex,       // mergePatchFaces
+            mergePatchFaces
             curvature,
             planarAngle,
             snapParams
@@ -1556,7 +1560,7 @@ int main(int argc, char *argv[])
             layerDict,
             motionDict,
             layerParams,
-            !keepHex,       //mergePatchFaces
+            mergePatchFaces,
             preBalance,
             decomposer,
             distributor

applications/utilities/mesh/generation/snappyHexMesh/snappyHexMeshDict

@@ -74,8 +74,7 @@ geometry
 
 // Optional: avoid patch-face merging. Allows mesh to be used for
 //           refinement/unrefinement
-//keepHex true;
-
+//mergePatchFaces    off; // default on
 
 // Settings for the castellatedMesh generation.
 castellatedMeshControls

src/mesh/autoMesh/autoHexMesh/autoHexMeshDriver/autoRefineDriver.C

@@ -1182,7 +1182,7 @@ void Foam::autoRefineDriver::addFaceZones
 
 void Foam::autoRefineDriver::mergePatchFaces
 (
-    const bool keepHex,
+    const bool geometricMerge,
     const refinementParameters& refineParams,
     const dictionary& motionDict
 )
@@ -1194,17 +1194,7 @@ void Foam::autoRefineDriver::mergePatchFaces
 
     const fvMesh& mesh = meshRefiner_.mesh();
 
-    if (keepHex)
-    {
-        meshRefiner_.mergePatchFaces
-        (
-            Foam::cos(degToRad(45.0)),
-            Foam::cos(degToRad(45.0)),
-            4,          // only merge faces split into 4
-            meshRefiner_.meshedPatches()
-        );
-    }
-    else
+    if (geometricMerge)
     {
         meshRefiner_.mergePatchFacesUndo
         (
@@ -1215,6 +1205,17 @@ void Foam::autoRefineDriver::mergePatchFaces
             labelList(mesh.nFaces(), -1)
         );
     }
+    else
+    {
+        // Still merge refined boundary faces if all four are on same patch
+        meshRefiner_.mergePatchFaces
+        (
+            Foam::cos(degToRad(45.0)),
+            Foam::cos(degToRad(45.0)),
+            4,          // only merge faces split into 4
+            meshRefiner_.meshedPatches()
+        );
+    }
 
     if (debug)
     {
@@ -1236,7 +1237,7 @@ void Foam::autoRefineDriver::doRefine
     const refinementParameters& refineParams,
     const snapParameters& snapParams,
     const bool prepareForSnapping,
-    const bool keepHex,
+    const bool doMergePatchFaces,
     const dictionary& motionDict
 )
 {
@@ -1328,7 +1329,7 @@ void Foam::autoRefineDriver::doRefine
     // Do something about cells with refined faces on the boundary
     if (prepareForSnapping)
     {
-        mergePatchFaces(keepHex, refineParams, motionDict);
+        mergePatchFaces(doMergePatchFaces, refineParams, motionDict);
     }
 
 

src/mesh/autoMesh/autoHexMesh/autoHexMeshDriver/autoRefineDriver.H

@@ -147,7 +147,7 @@ class autoRefineDriver
         //- Merge refined boundary faces (from exposing coarser cell)
         void mergePatchFaces
         (
-            const bool keepHex,
+            const bool geometricMerge,
             const refinementParameters& refineParams,
             const dictionary& motionDict
         );
@@ -187,7 +187,7 @@ public:
             const refinementParameters& refineParams,
             const snapParameters& snapParams,
             const bool prepareForSnapping,
-            const bool keepHexOnly,
+            const bool mergePatchFaces,
             const dictionary& motionDict
         );
 

tutorials/multiphase/interDyMFoam/ras/motorBike/system/snappyHexMeshDict

@@ -38,7 +38,7 @@ geometry
 
 // Optional: avoid patch-face merging. Allows mesh to be used for
 //           refinement/unrefinement
-keepHex true;
+mergePatchFaces off; // default on