functionObjects: nearWallFields: Fixed failed patch faces

Corrected a few issues with the utilisation of the tracking within the
nearWallFields function object. The tracking is now done over a
displacement from the initial location, which prevents trying to track
to a location outside the mesh when the patch face is warped and the
centre lies outside the tracking decomposition. Also fixed the end
criteria so that it does not suffer from round off error in the step
fraction.

The upshot of these changes is that the faces on which the near wall
cells were not being set are now being set properly, and uninitialised
data is no longer being written out.

src/functionObjects/field/nearWallFields/findCellParticle.C

@@ -34,13 +34,12 @@ Foam::findCellParticle::findCellParticle
     const label celli,
     const label tetFacei,
     const label tetPtI,
-    const point& end,
+    const vector& displacement,
     const label data
 )
 :
     particle(mesh, coordinates, celli, tetFacei, tetPtI),
-    start_(position()),
-    end_(end),
+    displacement_(displacement),
     data_(data)
 {}
 
@@ -50,13 +49,12 @@ Foam::findCellParticle::findCellParticle
     const polyMesh& mesh,
     const vector& position,
     const label celli,
-    const point& end,
+    const vector& displacement,
     const label data
 )
 :
     particle(mesh, position, celli),
-    start_(this->position()),
-    end_(end),
+    displacement_(displacement),
     data_(data)
 {}
 
@@ -74,15 +72,15 @@ Foam::findCellParticle::findCellParticle
     {
         if (is.format() == IOstream::ASCII)
         {
-            is >> start_ >> end_;
+            is >> displacement_;
             data_ = readLabel(is);
         }
         else
         {
             is.read
             (
-                reinterpret_cast<char*>(&start_),
-                sizeof(start_) + sizeof(end_) + sizeof(data_)
+                reinterpret_cast<char*>(&displacement_),
+                sizeof(displacement_) + sizeof(data_)
             );
         }
     }
@@ -111,10 +109,10 @@ bool Foam::findCellParticle::move
     while (td.keepParticle && !td.switchProcessor && stepFraction() < 1)
     {
         const scalar f = 1 - stepFraction();
-        trackToAndHitFace(f*(end_ - start_), f, cloud, td);
+        trackToAndHitFace(f*displacement_, f, cloud, td);
     }
 
-    if (stepFraction() == 1 || !td.keepParticle)
+    if (!td.switchProcessor)
     {
         // Hit endpoint or patch. If patch hit could do fancy stuff but just
         // to use the patch point is good enough for now.
@@ -229,8 +227,7 @@ Foam::Ostream& Foam::operator<<(Ostream& os, const findCellParticle& p)
     if (os.format() == IOstream::ASCII)
     {
         os  << static_cast<const particle&>(p)
-            << token::SPACE << p.start_
-            << token::SPACE << p.end_
+            << token::SPACE << p.displacement_
             << token::SPACE << p.data_;
     }
     else
@@ -238,8 +235,8 @@ Foam::Ostream& Foam::operator<<(Ostream& os, const findCellParticle& p)
         os  << static_cast<const particle&>(p);
         os.write
         (
-            reinterpret_cast<const char*>(&p.start_),
-            sizeof(p.start_) + sizeof(p.end_) + sizeof(p.data_)
+            reinterpret_cast<const char*>(&p.displacement_),
+            sizeof(p.displacement_) + sizeof(p.data_)
         );
     }
 

src/functionObjects/field/nearWallFields/findCellParticle.H

@@ -63,11 +63,8 @@ class findCellParticle
 {
     // Private data
 
-        //- Start point to track from
-        point start_;
-
-        //- End point to track to
-        point end_;
+        //- Displacement over which to track
+        vector displacement_;
 
         //- Passive data
         label data_;
@@ -126,7 +123,7 @@ public:
             const label celli,
             const label tetFacei,
             const label tetPtI,
-            const point& end,
+            const vector& displacement,
             const label data
         );
 
@@ -137,7 +134,7 @@ public:
             const polyMesh& mesh,
             const vector& position,
             const label celli,
-            const point& end,
+            const vector& displacement,
             const label data
         );
 
@@ -180,28 +177,16 @@ public:
 
     // Member Functions
 
-        //- Point to track from
-        const point& start() const
+        //- Displacement over which to track
+        const vector& displacement() const
         {
-            return start_;
+            return displacement_;
         }
 
-        //- Point to track from
-        point& start()
+        //- Displacement over which to track
+        vector& displacement()
         {
-            return start_;
-        }
-
-        //- Point to track to
-        const point& end() const
-        {
-            return end_;
-        }
-
-        //- Point to track to
-        point& end()
-        {
-            return end_;
+            return displacement_;
         }
 
         //- Transported label

src/functionObjects/field/nearWallFields/nearWallFields.C

@@ -79,17 +79,14 @@ void Foam::functionObjects::nearWallFields::calcAddressing()
 
         forAll(patch, patchFacei)
         {
-            const point& start = patch.Cf()[patchFacei];
-            const point end = start - distance_*nf[patchFacei];
-
             cloud.addParticle
             (
                 new findCellParticle
                 (
                     mesh_,
-                    start,
+                    patch.Cf()[patchFacei],
                     patch.faceCells()[patchFacei],
-                    end,
+                    - distance_*nf[patchFacei],
                     globalWalls.toGlobal(nPatchFaces) // passive data
                 )
             );
@@ -112,8 +109,8 @@ void Foam::functionObjects::nearWallFields::calcAddressing()
 
         forAllConstIter(Cloud<findCellParticle>, cloud, iter)
         {
-            const findCellParticle& tp = iter();
-            str.write(linePointRef(tp.position(), tp.end()));
+            const vector p = iter().position();
+            str.write(linePointRef(p, p + iter().displacement()));
         }
     }