Revert "Adding constraint of tracking motion in reduced dimension cases."

This reverts commit 9d3f0eaefb.

Need to do rigorously including implications for gathering data.

Bird's method for a 2D code involves all vector quantities being
actually 2D, and the density (for example) being particles per unit
area (flowfield) or length (surface).  Needs some thought to
generalise.

src/lagrangian/dsmc/Make/options

@@ -1,9 +1,7 @@
 EXE_INC = \
     -I$(LIB_SRC)/finiteVolume/lnInclude \
-    -I$(LIB_SRC)/lagrangian/basic/lnInclude \
+    -I$(LIB_SRC)/lagrangian/basic/lnInclude
-    -I$(LIB_SRC)/meshTools/lnInclude
 
 LIB_LIBS = \
     -llagrangian \
-    -lfiniteVolume \
+    -lfiniteVolume
-    -lmeshTools

src/lagrangian/dsmc/parcels/Templates/DsmcParcel/DsmcParcel.C

@@ -25,7 +25,6 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "DsmcParcel.H"
-#include "meshTools.H"
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
@@ -48,18 +47,8 @@ bool Foam::DsmcParcel<ParcelType>::move
     scalar tEnd = (1.0 - p.stepFraction())*deltaT;
     const scalar dtMax = tEnd;
 
-    // Save the velocity to re-apply it after tracking
-    vector U_save = U_;
-
-    // Apply correction to velocity to constrain tracking for
-    // reduced-D cases
-    meshTools::constrainDirection(mesh, mesh.solutionD(), U_);
-
     while (td.keepParticle && !td.switchProcessor && tEnd > ROOTVSMALL)
     {
-        // Apply correction to position for reduced-D cases
-        meshTools::constrainToMeshCentre(mesh, p.position());
-
         // Set the Lagrangian time-step
         scalar dt = min(dtMax, tEnd);
 
@@ -78,9 +67,6 @@ bool Foam::DsmcParcel<ParcelType>::move
         }
     }
 
-    // Restore the correct value of velocity
-    U_ = U_save;
-
     return td.keepParticle;
 }