From 1aa09612e5a1eaa31dd41d39a3064006e2b4ed45 Mon Sep 17 00:00:00 2001
From: Henry <Henry>
Date: Mon, 8 Apr 2013 15:38:22 +0100
Subject: [PATCH] wallGradU: Calculate patch gradient only on wall patches

---
 .../postProcessing/wall/wallGradU/wallGradU.C    | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/applications/utilities/postProcessing/wall/wallGradU/wallGradU.C b/applications/utilities/postProcessing/wall/wallGradU/wallGradU.C
index 8ea4dadafc..6491f2b1f9 100644
--- a/applications/utilities/postProcessing/wall/wallGradU/wallGradU.C
+++ b/applications/utilities/postProcessing/wall/wallGradU/wallGradU.C
@@ -30,6 +30,7 @@ Description
 \*---------------------------------------------------------------------------*/
 
 #include "fvCFD.H"
+#include "wallFvPatch.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -37,9 +38,9 @@ int main(int argc, char *argv[])
 {
     timeSelector::addOptions();
     #include "setRootCase.H"
-#   include "createTime.H"
+    #include "createTime.H"
     instantList timeDirs = timeSelector::select0(runTime, args);
-#   include "createMesh.H"
+    #include "createMesh.H"
 
     forAll(timeDirs, timeI)
     {
@@ -83,10 +84,17 @@ int main(int argc, char *argv[])
                 )
             );
 
+            const fvPatchList& patches = mesh.boundary();
+
             forAll(wallGradU.boundaryField(), patchi)
             {
-                wallGradU.boundaryField()[patchi] =
-                    -U.boundaryField()[patchi].snGrad();
+                const fvPatch& currPatch = patches[patchi];
+
+                if (isA<wallFvPatch>(currPatch))
+                {
+                    wallGradU.boundaryField()[patchi] =
+                        -U.boundaryField()[patchi].snGrad();
+                }
             }
 
             wallGradU.write();