Added virtual function for fvPatch slicing: support for immersed boundary

src/finiteVolume/fvMesh/fvPatches/constraint/empty/emptyFvPatch.H

@@ -74,11 +74,18 @@ public:
 
         // Access
 
+            //- Return patch size
             virtual label size() const
             {
                 return 0;
             }
 
+            //- Return patch slice size
+            virtual label sliceSize() const
+            {
+                return 0;
+            }
+
             //- Return faceCells of zero size
             virtual const unallocLabelList& faceCells() const;
 };

src/finiteVolume/fvMesh/fvPatches/fvPatch/fvPatch.H

@@ -191,12 +191,18 @@ public:
                 return polyPatch_.name();
             }
 
-            //- Return size
+            //- Return patch size
             virtual label size() const
             {
                 return polyPatch_.size();
             }
 
+            //- Return patch slice size.  Immersed boundary support
+            virtual label sliceSize() const
+            {
+                return size();
+            }
+
             //- Return true if this patch is coupled
             virtual bool coupled() const
             {
@@ -233,11 +239,12 @@ public:
             {
                 return typename List<T>::subList
                 (
-                    l, size(),
+                    l, sliceSize(),
                     polyPatch_.start()
                 );
             }
 
+            //- Slice list to patch
             template<class T>
             const typename Field<T>::subField patchSlice
             (
@@ -246,7 +253,7 @@ public:
             {
                 return typename Field<T>::subField
                 (
-                    l, size(),
+                    l, sliceSize(),
                     polyPatch_.start()
                 );
             }

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatch/immersedBoundaryFvPatch.H

@@ -152,6 +152,14 @@ public:
             //- Return size equal to number of intersected cells
             virtual label size() const;
 
+            //- Return patch slice size
+            //  Note: since the immersed boundary patch keeps the faces
+            //  in a separate list, slicing is not allowed.  HJ, 10/Oct/2018
+            virtual label sliceSize() const
+            {
+                return 0;
+            }
+
             //- Return faceCells next to the IB surface
             virtual const unallocLabelList& faceCells() const;