diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
index 9a2a7cd19b..db8165edcf 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.C
@@ -172,7 +172,7 @@ void Foam::KinematicCloud<ParcelType>::solve
 
         evolveCloud(td);
 
-        td.cloud().relaxSources();
+        td.cloud().relaxSources(td.cloud().cloudCopy());
     }
 
     td.cloud().info();
@@ -545,13 +545,13 @@ Foam::KinematicCloud<ParcelType>::KinematicCloud
     Cloud<ParcelType>(c.mesh(), name, c),
     kinematicCloud(),
     cloudCopyPtr_(NULL),
-    mesh_(c.mesh()),
+    mesh_(c.mesh_),
     particleProperties_(c.particleProperties_),
     solution_(c.solution_),
     constProps_(c.constProps_),
     subModelProperties_(c.subModelProperties_),
     rndGen_(c.rndGen_, true),
-    cellOccupancyPtr_(c.cellOccupancyPtr_->clone()),
+    cellOccupancyPtr_(NULL),
     rho_(c.rho_),
     U_(c.U_),
     mu_(c.mu_),
@@ -578,9 +578,7 @@ Foam::KinematicCloud<ParcelType>::KinematicCloud
                 IOobject::NO_WRITE,
                 false
             ),
-            mesh_,
-            c.UTrans_().dimensions(),
-            c.UTrans_().field()
+            c.UTrans_()
         )
     ),
     UCoeff_
@@ -722,9 +720,12 @@ void Foam::KinematicCloud<ParcelType>::relax
 
 
 template<class ParcelType>
-void Foam::KinematicCloud<ParcelType>::relaxSources()
+void Foam::KinematicCloud<ParcelType>::relaxSources
+(
+    const KinematicCloud<ParcelType>& cloudOldTime
+)
 {
-    this->relax(UTrans_(), cloudCopyPtr_->UTrans(), "U");
+    this->relax(UTrans_(), cloudOldTime.UTrans(), "U");
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
index a43f20cbb7..74c2c03909 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloud.H
@@ -418,6 +418,9 @@ public:
 
         // Access
 
+            //- Return a reference to the cloud copy
+            inline const KinematicCloud& cloudCopy() const;
+
             //- If the collision model controls the wall interaction,
             //  then the wall impact distance should be zero.
             //  Otherwise, it should be allowed to be the value from
@@ -615,7 +618,7 @@ public:
             ) const;
 
             //- Apply relaxation to (steady state) cloud sources
-            void relaxSources();
+            void relaxSources(const KinematicCloud<ParcelType>& cloudOldTime);
 
             //- Evolve the cloud
             void evolve();
diff --git a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
index 3643f52cd5..4b8c87e3cd 100644
--- a/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/KinematicCloud/KinematicCloudI.H
@@ -126,6 +126,14 @@ Foam::KinematicCloud<ParcelType>::cloudSolution::resetSourcesOnStartup() const
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class ParcelType>
+inline const KinematicCloud<ParcelType>&
+Foam::KinematicCloud<ParcelType>::cloudCopy() const
+{
+    return cloudCopyPtr_();
+}
+
+
 template<class ParcelType>
 inline bool Foam::KinematicCloud<ParcelType>::hasWallImpactDistance() const
 {
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
index bb4938849f..dfebcebc85 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.C
@@ -275,16 +275,19 @@ void Foam::ReactingCloud<ParcelType>::resetSourceTerms()
 
 
 template<class ParcelType>
-void Foam::ReactingCloud<ParcelType>::relaxSources()
+void Foam::ReactingCloud<ParcelType>::relaxSources
+(
+    const ReactingCloud<ParcelType>& cloudOldTime
+)
 {
-    ThermoCloud<ParcelType>::relaxSources();
+    typedef DimensionedField<scalar, volMesh> dsfType;
+
+    ThermoCloud<ParcelType>::relaxSources(cloudOldTime);
 
     forAll(rhoTrans_, fieldI)
     {
-        DimensionedField<scalar, volMesh>& rhoT =
-            rhoTrans_[fieldI];
-        const DimensionedField<scalar, volMesh>& rhoT0 =
-            cloudCopyPtr_->rhoTrans()[fieldI];
+        dsfType& rhoT = rhoTrans_[fieldI];
+        const dsfType& rhoT0 = cloudOldTime.rhoTrans()[fieldI];
         this->relax(rhoT, rhoT0, "rho");
     }
 }
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
index c968a723f1..1b16c4b5aa 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloud.H
@@ -191,6 +191,9 @@ public:
 
         // Access
 
+            //- Return a reference to the cloud copy
+            inline const ReactingCloud& cloudCopy() const;
+
             //- Return the constant properties
             inline const typename ParcelType::constantProperties&
                 constProps() const;
@@ -215,6 +218,10 @@ public:
                     inline DimensionedField<scalar, volMesh>&
                         rhoTrans(const label i);
 
+                    //- Return const access to mass source fields
+                    inline const PtrList<DimensionedField<scalar, volMesh> >&
+                        rhoTrans() const;
+
                     //- Return reference to mass source fields
                     inline PtrList<DimensionedField<scalar, volMesh> >&
                         rhoTrans();
@@ -264,7 +271,7 @@ public:
             void resetSourceTerms();
 
             //- Apply relaxation to (steady state) cloud sources
-            void relaxSources();
+            void relaxSources(const ReactingCloud<ParcelType>& cloudOldTime);
 
             //- Evolve the cloud
             void evolve();
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloudI.H b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloudI.H
index b9c23839ec..f1c931d17c 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingCloud/ReactingCloudI.H
@@ -25,6 +25,14 @@ License
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class ParcelType>
+inline const ReactingCloud<ParcelType>&
+Foam::ReactingCloud<ParcelType>::cloudCopy() const
+{
+    return cloudCopyPtr_();
+}
+
+
 template<class ParcelType>
 inline const typename ParcelType::constantProperties&
 Foam::ReactingCloud<ParcelType>::constProps() const
@@ -57,6 +65,15 @@ Foam::ReactingCloud<ParcelType>::rhoTrans(const label i)
 }
 
 
+template<class ParcelType>
+inline
+const Foam::PtrList<Foam::DimensionedField<Foam::scalar, Foam::volMesh> >&
+Foam::ReactingCloud<ParcelType>::rhoTrans() const
+{
+    return rhoTrans_;
+}
+
+
 template<class ParcelType>
 inline Foam::PtrList<Foam::DimensionedField<Foam::scalar, Foam::volMesh> >&
 Foam::ReactingCloud<ParcelType>::rhoTrans()
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
index 2a554c5b36..8226112fd7 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloud.H
@@ -187,6 +187,9 @@ public:
 
         // Access
 
+            //- Return a reference to the cloud copy
+            inline const ReactingMultiphaseCloud& cloudCopy() const;
+
             //- Return the constant properties
             inline const typename ParcelType::constantProperties&
                 constProps() const;
diff --git a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloudI.H b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloudI.H
index 87130d22cb..354f38985c 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ReactingMultiphaseCloud/ReactingMultiphaseCloudI.H
@@ -25,6 +25,14 @@ License
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class ParcelType>
+inline const ReactingMultiphaseCloud<ParcelType>&
+Foam::ReactingMultiphaseCloud<ParcelType>::cloudCopy() const
+{
+    return cloudCopyPtr_();
+}
+
+
 template<class ParcelType>
 inline const typename ParcelType::constantProperties&
 Foam::ReactingMultiphaseCloud<ParcelType>::constProps() const
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
index 61a19d4762..346367e5b7 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.C
@@ -272,11 +272,14 @@ void Foam::ThermoCloud<ParcelType>::resetSourceTerms()
 
 
 template<class ParcelType>
-void Foam::ThermoCloud<ParcelType>::relaxSources()
+void Foam::ThermoCloud<ParcelType>::relaxSources
+(
+    const ThermoCloud<ParcelType>& cloudOldTime
+)
 {
-    KinematicCloud<ParcelType>::relaxSources();
+    KinematicCloud<ParcelType>::relaxSources(cloudOldTime);
 
-    this->relax(hsTrans_(), cloudCopyPtr_->hsTrans(), "hs");
+    this->relax(hsTrans_(), cloudOldTime.hsTrans(), "hs");
 }
 
 
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
index 0d5a75f4ae..a46c3c5621 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloud.H
@@ -191,6 +191,9 @@ public:
 
         // Access
 
+            //- Return a reference to the cloud copy
+            inline const ThermoCloud& cloudCopy() const;
+
             //- Return the constant properties
             inline const typename ParcelType::constantProperties&
                 constProps() const;
@@ -278,7 +281,7 @@ public:
             void resetSourceTerms();
 
             //- Apply relaxation to (steady state) cloud sources
-            void relaxSources();
+            void relaxSources(const ThermoCloud<ParcelType>& cloudOldTime);
 
             //- Evolve the cloud
             void evolve();
diff --git a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
index 79e26fa166..15d2d775d7 100644
--- a/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
+++ b/src/lagrangian/intermediate/clouds/Templates/ThermoCloud/ThermoCloudI.H
@@ -29,6 +29,14 @@ using namespace Foam::constant;
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+template<class ParcelType>
+inline const ThermoCloud<ParcelType>&
+Foam::ThermoCloud<ParcelType>::cloudCopy() const
+{
+    return cloudCopyPtr_();
+}
+
+
 template<class ParcelType>
 inline const typename ParcelType::constantProperties&
 Foam::ThermoCloud<ParcelType>::constProps() const