ENH: snappyHexMesh: improvements to gap detection:

- shoot rays to nearest point on surface and two perpendicular rays
  (instead of always shooting in the 3 coordinate directions)

- avoid bleeding through the surface intersection

src/mesh/autoMesh/autoHexMesh/meshRefinement/meshRefinementGapRefine.C

@@ -1366,14 +1366,17 @@ Foam::label Foam::meshRefinement::markInternalGapRefinement
                 << mesh_.globalData().nTotalFaces() << endl;
 
 
-            FaceCellWave<transportData> deltaCalc
+            transportData::trackData td(surfaceIndex_);
+
+            FaceCellWave<transportData, transportData::trackData> deltaCalc
             (
                 mesh_,
                 frontFaces,
                 frontData,
                 faceData,
                 cellData,
-                mesh_.globalData().nTotalCells()+1
+                mesh_.globalData().nTotalCells()+1,
+                td
             );
 
 

src/mesh/autoMesh/autoHexMesh/meshRefinement/transportData.H

@@ -45,7 +45,6 @@ namespace Foam
 
 // Forward declaration of classes
 class polyMesh;
-class hexRef8;
 
 /*---------------------------------------------------------------------------*\
                            Class transportData Declaration
@@ -55,6 +54,23 @@ class transportData
 :
     public wallPointData<scalar>
 {
+public:
+
+    //- Class used to pass additional data in
+    class trackData
+    {
+    public:
+
+        //- Per face the index of the surface hit
+        const labelList& surfaceIndex_;
+
+        trackData(const labelList& surfaceIndex)
+        :
+            surfaceIndex_(surfaceIndex)
+        {}
+    };
+
+
 private:
 
     // Private Member Functions

src/mesh/autoMesh/autoHexMesh/meshRefinement/transportDataI.H

@@ -101,12 +101,17 @@ inline bool Foam::transportData::updateCell
 (
     const polyMesh& mesh,
     const label cellI,
-    const label,
+    const label faceI,
     const transportData& neighbourWallInfo,
     const scalar tol,
     TrackingData& td
 )
 {
+    if (td.surfaceIndex_[faceI] != -1)
+    {
+        return false;
+    }
+
     const vectorField& cellCentres = mesh.primitiveMesh::cellCentres();
 
     bool updated = update
@@ -132,6 +137,11 @@ inline bool Foam::transportData::updateFace
     TrackingData& td
 )
 {
+    if (td.surfaceIndex_[thisFaceI] != -1)
+    {
+        return false;
+    }
+
     return update
     (
         mesh.faceCentres()[thisFaceI],
@@ -152,6 +162,11 @@ inline bool Foam::transportData::updateFace
     TrackingData& td
 )
 {
+    if (td.surfaceIndex_[thisFaceI] != -1)
+    {
+        return false;
+    }
+
     return update
     (
         mesh.faceCentres()[thisFaceI],