diff --git a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.H b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.H
index 88bc69d5..2912d960 100644
--- a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.H
+++ b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.H
@@ -373,6 +373,7 @@ public:
 
        inline const wordList& forceModels() const;
 
+       inline voidFractionModel& voidFractionM();
        inline const voidFractionModel& voidFractionM() const;
 
        inline const locateModel& locateM() const;
diff --git a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloudI.H b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloudI.H
index d32a89e5..2ab8d0fe 100644
--- a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloudI.H
+++ b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloudI.H
@@ -319,9 +319,15 @@ inline probeModel& cfdemCloud::probeM()
     return probeModel_();
 }
 
+inline voidFractionModel& cfdemCloud::voidFractionM()
+{
+    return voidFractionModel_();
+}
+
 inline const voidFractionModel& cfdemCloud::voidFractionM() const
 {
-    return voidFractionModel_;
+    return voidFractionModel_();
+}
 
 inline averagingModel& cfdemCloud::averagingM()
 {
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.C
index 595f17c2..9a8c5a22 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.C
@@ -87,7 +87,7 @@ GaussVoidFraction::~GaussVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void GaussVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV) const
+void GaussVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV)
 {
     reAllocArrays();
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.H
index 535166ba..0a84508d 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/GaussVoidFraction/GaussVoidFraction.H
@@ -63,7 +63,7 @@ private:
 
         const scalar alphaMin_;          //NP min value of voidFraction
 
-	    mutable bool alphaLimited_;
+        bool alphaLimited_;
 
 public:
 
@@ -86,7 +86,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 
         void buildLabelHashSet
         (
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.C
index eeb7ad2e..fcc1947b 100755
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.C
@@ -87,7 +87,7 @@ IBVoidFraction::~IBVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void IBVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV) const
+void IBVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV)
 {
     const boundBox& globalBb = particleCloud_.mesh().bounds();
 
@@ -306,7 +306,7 @@ void IBVoidFraction::buildLabelHashSet
     const label cellID,
     labelHashSet& hashSett,
     bool initialInsert //initial insertion of own cell
-)const
+)
 {
     if(initialInsert)
         hashSett.insert(cellID);
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.H
index 0e430dc9..7f43e3f8 100755
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/IBVoidFraction/IBVoidFraction.H
@@ -64,7 +64,7 @@ private:
 
         const scalar alphaMin_;          //NP min value of voidFraction
 
-        mutable bool alphaLimited_;
+        bool alphaLimited_;
 
         const scalar scaleUpVol_;        //NP scaling radius, keeping volume of particle
 
@@ -91,7 +91,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 
         void buildLabelHashSet
         (
@@ -100,7 +100,7 @@ public:
             const label cellID,
             labelHashSet& hashSett,
             bool          initialInsert
-        ) const;
+        );
 
         virtual double segmentParticleIntersection(int index, vector positionCenter, vector pointInside, vector pointOutside) const;
 };
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.C
index 1ab0de24..4d254b42 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.C
@@ -86,7 +86,7 @@ bigParticleVoidFraction::~bigParticleVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void bigParticleVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV) const
+void bigParticleVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV)
 {
     reAllocArrays();
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.H
index 8e470a44..2875efb5 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/bigParticleVoidFraction/bigParticleVoidFraction.H
@@ -60,7 +60,7 @@ private:
 
         const scalar alphaMin_;          // min value of voidFraction
 
-        mutable bool alphaLimited_;
+        bool alphaLimited_;
 
 public:
 
@@ -83,7 +83,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 
         void buildLabelHashSet
         (
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.C
index 6aa96bce..355211cc 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.C
@@ -78,7 +78,7 @@ centreVoidFraction::~centreVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void centreVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV) const
+void centreVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV)
 {
     reAllocArrays();
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.H
index 15199923..bf6375ad 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/centreVoidFraction/centreVoidFraction.H
@@ -60,7 +60,7 @@ private:
 
         const scalar alphaMin_;          //NP min value of voidFraction
 
-	mutable bool alphaLimited_;
+        bool alphaLimited_;
 
 public:
 
@@ -83,7 +83,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 };
 
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.C
index 6b3da2c8..979bf064 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.C
@@ -156,7 +156,7 @@ dividedVoidFraction::~dividedVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void dividedVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes, double**& particleV) const
+void dividedVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes, double**& particleV)
 {
     if (cfdemUseOnly_)
         reAllocArrays(particleCloud_.numberOfParticles());
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.H
index 6cde9f28..de8c5409 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/dividedVoidFraction/dividedVoidFraction.H
@@ -68,9 +68,9 @@ private:
 
         const scalar alphaMin_;          // min value of voidFraction
 
-        mutable bool alphaLimited_;
+        bool alphaLimited_;
 
-        mutable scalar tooMuch_;         // particle volume which is lost due to voidFraction limitation
+        scalar tooMuch_;         // particle volume which is lost due to voidFraction limitation
 
         const bool interpolation_;
 
@@ -104,7 +104,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 };
 
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.C
index 8413532a..c43e3c9f 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.C
@@ -88,7 +88,7 @@ trilinearVoidFraction::~trilinearVoidFraction()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void trilinearVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV) const
+void trilinearVoidFraction::setvoidFraction(double** const& mask,double**& voidfractions,double**& particleWeights,double**& particleVolumes,double**& particleV)
 {
     reAllocArrays();
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.H
index 08a3bdd7..2a821fbe 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/trilinearVoidFraction/trilinearVoidFraction.H
@@ -88,7 +88,7 @@ public:
 
 
     // Member Functions
-        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&) const;
+        void setvoidFraction(double** const& ,double**&, double**&, double**&, double**&);
 };
 
 
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.C b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.C
index 424b8eef..b2e85c9e 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.C
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.C
@@ -112,7 +112,7 @@ tmp<volScalarField> voidFractionModel::voidFractionInterp() const
     );
 }
 
-void voidFractionModel::resetVoidFractions() const
+void voidFractionModel::resetVoidFractions()
 {
     voidfractionPrev_.ref() = voidfractionNext_.ref();
     voidfractionNext_.ref() = 1.;
@@ -128,7 +128,7 @@ int voidFractionModel::maxCellsPerParticle() const
     return maxCellsPerParticle_;
 }
 
-void voidFractionModel::reAllocArrays() const
+void voidFractionModel::reAllocArrays()
 {
     if(particleCloud_.numberOfParticlesChanged())
     {
@@ -137,7 +137,7 @@ void voidFractionModel::reAllocArrays() const
     }
 }
 
-void voidFractionModel::reAllocArrays(int nP) const
+void voidFractionModel::reAllocArrays(int nP)
 {
     if(particleCloud_.numberOfParticlesChanged())
     {
diff --git a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.H b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.H
index 9a760b31..0f1a47d3 100644
--- a/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.H
+++ b/src/lagrangian/cfdemParticle/subModels/voidFractionModel/voidFractionModel/voidFractionModel.H
@@ -65,17 +65,17 @@ protected:
 
         bool multiWeights_;
 
-        mutable volScalarField voidfractionPrev_;
+        volScalarField voidfractionPrev_;
 
-        mutable volScalarField voidfractionNext_;
+        volScalarField voidfractionNext_;
 
-        mutable int ** cellsPerParticle_;
+        int ** cellsPerParticle_;
 
         int maxCellsPerParticle_;
 
-        mutable scalar weight_;
+        scalar weight_;
 
-        mutable scalar porosity_;
+        scalar porosity_;
 
     // Protected member functions
 
@@ -124,30 +124,32 @@ public:
 
 
     // public member functions
-        virtual void setvoidFraction(double** const&,double**&,double**&,double**&,double**&) const = 0;
+        virtual void setvoidFraction(double** const&,double**&,double**&,double**&,double**&) = 0;
 
         tmp<volScalarField> voidFractionInterp() const;
 
-        inline volScalarField& voidFractionPrev()const { return voidfractionPrev_; }
+        volScalarField& voidFractionPrev() { return voidfractionPrev_; }
+        const volScalarField& voidFractionPrev() const { return voidfractionPrev_; }
 
-        inline volScalarField& voidFractionNext()const { return voidfractionNext_; }
+        volScalarField& voidFractionNext() { return voidfractionNext_; }
+        const volScalarField& voidFractionNext() const { return voidfractionNext_; }
 
-        inline scalar weight()const { return weight_; }
+        scalar weight() const { return weight_; }
 
-        inline scalar weight(label index) const
+        scalar weight(label index) const
         {
             return particleCloud_.particleEffVolFactor(index);
         }
 
-        inline scalar porosity()const { return porosity_; }
+        scalar porosity() const { return porosity_; }
 
-        inline void checkWeightNporosity(dictionary& propsDict) const
+        void checkWeightNporosity(dictionary& propsDict)
         {
             if (propsDict.found("weight")) weight_ = readScalar(propsDict.lookup("weight"));
             if (propsDict.found("porosity")) porosity_ = readScalar(propsDict.lookup("porosity"));
         }
 
-        void resetVoidFractions() const;
+        void resetVoidFractions();
 
         //void undoVoidFractions(double**const&) const;
 
@@ -155,9 +157,9 @@ public:
 
         int maxCellsPerParticle() const;
 
-        void reAllocArrays() const;
+        void reAllocArrays();
 
-        void reAllocArrays(int nP) const;  //force number of particles during reallocation, for CFD offline-use
+        void reAllocArrays(int nP);  //force number of particles during reallocation, for CFD offline-use
 
         virtual void setParticleType(label type) const {}