From f4fd4c00dc807947f59c13d3bc55003e01df2f65 Mon Sep 17 00:00:00 2001
From: graham <g.macpherson@opencfd.co.uk>
Date: Tue, 25 May 2010 19:46:58 +0100
Subject: [PATCH] ENH: Adding per-patch wall interaction.

Rearranged data storage in existing wall model.  Improved stability.
---
 .../WallCollisionRecordI.H                    |   2 +-
 .../include/makeParcelCollisionModels.H       |   8 +
 .../makeReactingParcelCollisionModels.H       |  10 +-
 .../PairSpringSliderDashpot.C                 |   4 +-
 .../PairSpringSliderDashpot.H                 |   5 +-
 .../WallLocalSpringSliderDashpot.C            | 354 ++++++++++++++++++
 .../WallLocalSpringSliderDashpot.H            | 184 +++++++++
 .../WallModel/WallModel/WallModel.C           |   8 +
 .../WallModel/WallModel/WallModel.H           |   3 +
 .../WallSpringSliderDashpot.C                 |  66 ++--
 .../WallSpringSliderDashpot.H                 |  14 +-
 11 files changed, 604 insertions(+), 54 deletions(-)
 create mode 100644 src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.C
 create mode 100644 src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.H

diff --git a/src/lagrangian/intermediate/parcels/Templates/KinematicParcel/CollisionRecordList/WallCollisionRecord/WallCollisionRecordI.H b/src/lagrangian/intermediate/parcels/Templates/KinematicParcel/CollisionRecordList/WallCollisionRecord/WallCollisionRecordI.H
index 1a9a9feb0b..42f5b4f421 100644
--- a/src/lagrangian/intermediate/parcels/Templates/KinematicParcel/CollisionRecordList/WallCollisionRecord/WallCollisionRecordI.H
+++ b/src/lagrangian/intermediate/parcels/Templates/KinematicParcel/CollisionRecordList/WallCollisionRecord/WallCollisionRecordI.H
@@ -39,7 +39,7 @@ inline bool Foam::WallCollisionRecord<Type>::match
     // Using the new data as the acceptance criterion
     scalar cosAcceptanceAngle = magpRel/radius;
 
-    if (cosAcceptanceAngle > 1.0)
+    if (cosAcceptanceAngle > 1.0 + SMALL)
     {
         Info<< "pRel_ " << pRel_ << " " << magpRel_ << nl
             << "pRel " << pRel << " " << magpRel << nl
diff --git a/src/lagrangian/intermediate/parcels/include/makeParcelCollisionModels.H b/src/lagrangian/intermediate/parcels/include/makeParcelCollisionModels.H
index 98ef4bfbe5..0c84d934bd 100644
--- a/src/lagrangian/intermediate/parcels/include/makeParcelCollisionModels.H
+++ b/src/lagrangian/intermediate/parcels/include/makeParcelCollisionModels.H
@@ -36,6 +36,7 @@ License
 #include "PairSpringSliderDashpot.H"
 
 #include "WallSpringSliderDashpot.H"
+#include "WallLocalSpringSliderDashpot.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -73,6 +74,13 @@ License
         WallSpringSliderDashpot,                                              \
         KinematicCloud,                                                       \
         ParcelType                                                            \
+    );                                                                        \
+                                                                              \
+    makeWallModelType                                                         \
+    (                                                                         \
+        WallLocalSpringSliderDashpot,                                         \
+        KinematicCloud,                                                       \
+        ParcelType                                                            \
     );
 
 
diff --git a/src/lagrangian/intermediate/parcels/include/makeReactingParcelCollisionModels.H b/src/lagrangian/intermediate/parcels/include/makeReactingParcelCollisionModels.H
index f1bd4af8a1..289615125f 100644
--- a/src/lagrangian/intermediate/parcels/include/makeReactingParcelCollisionModels.H
+++ b/src/lagrangian/intermediate/parcels/include/makeReactingParcelCollisionModels.H
@@ -37,6 +37,7 @@ License
 #include "PairSpringSliderDashpot.H"
 
 #include "WallSpringSliderDashpot.H"
+#include "WallLocalSpringSliderDashpot.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -99,9 +100,16 @@ License
         KinematicCloud,                                                       \
         ParcelType,                                                           \
         ThermoType                                                            \
+    );                                                                        \
+                                                                              \
+    makeWallModelThermoType                                                   \
+    (                                                                         \
+        WallLocalSpringSliderDashpot,                                         \
+        KinematicCloud,                                                       \
+        ParcelType,                                                           \
+        ThermoType                                                            \
     );
 
-
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 #endif
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.C b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.C
index ad3f95ad49..fb732aa19d 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.C
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.C
@@ -100,11 +100,11 @@ Foam::PairSpringSliderDashpot<CloudType>::PairSpringSliderDashpot
         )
     ),
     volumeFactor_(1.0),
-    useEquivalentSize_(Switch(this->dict().lookup("useEquivalentSize")))
+    useEquivalentSize_(Switch(this->coeffDict().lookup("useEquivalentSize")))
 {
     if (useEquivalentSize_)
     {
-        volumeFactor_ = readScalar(this->dict().lookup("volumeFactor"));
+        volumeFactor_ = readScalar(this->coeffDict().lookup("volumeFactor"));
     }
 
     scalar nu = this->owner().constProps().poissonsRatio();
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.H b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.H
index a8982b57eb..9fba1b35e7 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.H
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.H
@@ -58,9 +58,6 @@ class PairSpringSliderDashpot
         //  the same Poisson's ratio and Young's modulus
         scalar Gstar_;
 
-        //- Poisson's ratio of both particles
-        scalar sigma_;
-
         //- alpha-coefficient, related to coefficient of restitution
         scalar alpha_;
 
@@ -93,7 +90,7 @@ class PairSpringSliderDashpot
         scalar volumeFactor_;
 
         //- Switch to control use of equivalent size particles.  Used
-        //  because cbrt calculation is very expensive.
+        //  because the calculation can be very expensive.
         bool useEquivalentSize_;
 
 
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.C b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.C
new file mode 100644
index 0000000000..996c35801d
--- /dev/null
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.C
@@ -0,0 +1,354 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2008-2010 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "WallLocalSpringSliderDashpot.H"
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+template <class CloudType>
+void Foam::WallLocalSpringSliderDashpot<CloudType>::findMinMaxProperties
+(
+    scalar& rMin,
+    scalar& rhoMax,
+    scalar& UMagMax
+) const
+{
+    rMin = VGREAT;
+    rhoMax = -VGREAT;
+    UMagMax = -VGREAT;
+
+    forAllConstIter(typename CloudType, this->owner(), iter)
+    {
+        const typename CloudType::parcelType& p = iter();
+
+        // Finding minimum diameter to avoid excessive arithmetic
+
+        scalar dEff = p.d();
+
+        if (useEquivalentSize_)
+        {
+            dEff *= cbrt(p.nParticle()*volumeFactor_);
+        }
+
+        rMin = min(dEff, rMin);
+
+        rhoMax = max(p.rho(), rhoMax);
+
+        UMagMax = max
+        (
+            mag(p.U()) + mag(p.omega())*dEff/2,
+            UMagMax
+        );
+    }
+
+    // Transform the minimum diameter into minimum radius
+    //     rMin = dMin/2
+
+    rMin /= 2.0;
+}
+
+
+template <class CloudType>
+void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
+(
+    typename CloudType::parcelType& p,
+    const point& site,
+    const WallSiteData<vector>& data,
+    scalar pREff
+) const
+{
+    // wall patch index
+    label wPI = patchMap_[data.patchIndex()];
+
+    // data for this patch
+    scalar Estar = Estar_[wPI];
+    scalar Gstar = Gstar_[wPI];
+    scalar alpha = alpha_[wPI];
+    scalar b = b_[wPI];
+    scalar mu = mu_[wPI];
+
+    vector r_PW = p.position() - site;
+
+    vector U_PW = p.U() - data.wallData();
+
+    scalar normalOverlapMag = max(pREff - mag(r_PW), 0.0);
+
+    vector rHat_PW = r_PW/(mag(r_PW) + VSMALL);
+
+    scalar kN = (4.0/3.0)*sqrt(pREff)*Estar;
+
+    scalar etaN = alpha*sqrt(p.mass()*kN)*pow025(normalOverlapMag);
+
+    vector fN_PW =
+        rHat_PW
+       *(kN*pow(normalOverlapMag, b) - etaN*(U_PW & rHat_PW));
+
+    p.f() += fN_PW;
+
+    vector USlip_PW =
+        U_PW - (U_PW & rHat_PW)*rHat_PW
+      + (p.omega() ^ (pREff*-rHat_PW));
+
+    scalar deltaT = this->owner().mesh().time().deltaTValue();
+
+    vector& tangentialOverlap_PW =
+        p.collisionRecords().matchWallRecord(-r_PW, pREff).collisionData();
+
+    tangentialOverlap_PW += USlip_PW*deltaT;
+
+    scalar tangentialOverlapMag = mag(tangentialOverlap_PW);
+
+    if (tangentialOverlapMag > VSMALL)
+    {
+        scalar kT = 8.0*sqrt(pREff*normalOverlapMag)*Gstar;
+
+        scalar etaT = etaN;
+
+        // Tangential force
+        vector fT_PW;
+
+        if (kT*tangentialOverlapMag > mu*mag(fN_PW))
+        {
+            // Tangential force greater than sliding friction,
+            // particle slips
+
+            fT_PW = -mu*mag(fN_PW)*USlip_PW/mag(USlip_PW);
+
+            tangentialOverlap_PW = vector::zero;
+        }
+        else
+        {
+            fT_PW =
+                -kT*tangentialOverlapMag
+               *tangentialOverlap_PW/tangentialOverlapMag
+              - etaT*USlip_PW;
+        }
+
+        p.f() += fT_PW;
+
+        p.torque() += (pREff*-rHat_PW) ^ fT_PW;
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+template <class CloudType>
+Foam::WallLocalSpringSliderDashpot<CloudType>::WallLocalSpringSliderDashpot
+(
+    const dictionary& dict,
+    CloudType& cloud
+)
+:
+    WallModel<CloudType>(dict, cloud, typeName),
+    Estar_(),
+    Gstar_(),
+    alpha_(),
+    b_(),
+    mu_(),
+    patchMap_(),
+    maxEstarIndex_(-1),
+    collisionResolutionSteps_
+    (
+        readScalar
+        (
+            this->coeffDict().lookup("collisionResolutionSteps")
+        )
+    ),
+    volumeFactor_(1.0),
+    useEquivalentSize_(Switch(this->coeffDict().lookup("useEquivalentSize")))
+{
+    if (useEquivalentSize_)
+    {
+        volumeFactor_ = readScalar(this->coeffDict().lookup("volumeFactor"));
+    }
+
+    scalar pNu = this->owner().constProps().poissonsRatio();
+
+    scalar pE = this->owner().constProps().youngsModulus();
+
+    const polyMesh& mesh = cloud.mesh();
+
+    const polyBoundaryMesh& bMesh = mesh.boundaryMesh();
+
+    patchMap_.setSize(bMesh.size(), -1);
+
+    DynamicList<label> wallPatchIndices;
+
+    forAll(bMesh, patchI)
+    {
+        if (isA<wallPolyPatch>(bMesh[patchI]))
+        {
+            wallPatchIndices.append(bMesh[patchI].index());
+        }
+    }
+
+    label nWallPatches = wallPatchIndices.size();
+
+    Estar_.setSize(nWallPatches);
+    Gstar_.setSize(nWallPatches);
+    alpha_.setSize(nWallPatches);
+    b_.setSize(nWallPatches);
+    mu_.setSize(nWallPatches);
+
+    scalar maxEstar = -GREAT;
+
+    forAll(wallPatchIndices, wPI)
+    {
+        const dictionary& patchCoeffDict
+        (
+            this->coeffDict().subDict(bMesh[wallPatchIndices[wPI]].name())
+        );
+
+        patchMap_[wallPatchIndices[wPI]] = wPI;
+
+        scalar nu = dimensionedScalar
+        (
+            patchCoeffDict.lookup("poissonsRatio")
+        ).value();
+
+        scalar E = dimensionedScalar
+        (
+            patchCoeffDict.lookup("youngsModulus")
+        ).value();
+
+        Estar_[wPI] = 1/((1 - sqr(pNu))/pE + (1 - sqr(nu))/E);
+
+        Gstar_[wPI] = 1/(2*((2 + pNu - sqr(pNu))/pE + (2 + nu - sqr(nu))/E));
+
+        alpha_[wPI] =
+            dimensionedScalar(patchCoeffDict.lookup("alpha")).value();
+
+        b_[wPI] = dimensionedScalar(patchCoeffDict.lookup("b")).value();
+
+        mu_[wPI] = dimensionedScalar(patchCoeffDict.lookup("mu")).value();
+
+        if (Estar_[wPI] > maxEstar)
+        {
+            maxEstarIndex_ = wPI;
+
+            maxEstar = Estar_[wPI];
+        }
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+template <class CloudType>
+Foam::WallLocalSpringSliderDashpot<CloudType>::~WallLocalSpringSliderDashpot()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+template<class CloudType>
+Foam::scalar Foam::WallLocalSpringSliderDashpot<CloudType>::pREff
+(
+    const typename CloudType::parcelType& p
+) const
+{
+    if (useEquivalentSize_)
+    {
+        return p.d()/2*cbrt(p.nParticle()*volumeFactor_);
+    }
+    else
+    {
+        return p.d()/2;
+    }
+}
+
+
+template<class CloudType>
+bool Foam::WallLocalSpringSliderDashpot<CloudType>::controlsTimestep() const
+{
+    return true;
+}
+
+
+template<class CloudType>
+Foam::label Foam::WallLocalSpringSliderDashpot<CloudType>::nSubCycles() const
+{
+    if (!(this->owner().size()))
+    {
+        return 1;
+    }
+
+    scalar rMin;
+    scalar rhoMax;
+    scalar UMagMax;
+
+    findMinMaxProperties(rMin, rhoMax, UMagMax);
+
+    // Note:  pi^(7/5)*(5/4)^(2/5) = 5.429675
+    scalar minCollisionDeltaT =
+        5.429675
+       *rMin
+       *pow(rhoMax/(Estar_[maxEstarIndex_]*sqrt(UMagMax) + VSMALL), 0.4)
+       /collisionResolutionSteps_;
+
+    return ceil(this->owner().time().deltaTValue()/minCollisionDeltaT);
+}
+
+
+template<class CloudType>
+void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
+(
+    typename CloudType::parcelType& p,
+    const List<point>& flatSitePoints,
+    const List<WallSiteData<vector> >& flatSiteData,
+    const List<point>& sharpSitePoints,
+    const List<WallSiteData<vector> >& sharpSiteData
+) const
+{
+    scalar pREff = this->pREff(p);
+
+    forAll(flatSitePoints, siteI)
+    {
+        evaluateWall
+        (
+            p,
+            flatSitePoints[siteI],
+            flatSiteData[siteI],
+            pREff
+        );
+    }
+
+    forAll(sharpSitePoints, siteI)
+    {
+        // Treating sharp sites like flat sites
+
+        evaluateWall
+        (
+            p,
+            sharpSitePoints[siteI],
+            sharpSiteData[siteI],
+            pREff
+        );
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.H b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.H
new file mode 100644
index 0000000000..4062c9928c
--- /dev/null
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.H
@@ -0,0 +1,184 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2008-2010 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::WallLocalSpringSliderDashpot
+
+Description
+    Forces between particles and walls, interacting with a spring,
+    slider, damper model
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef WallLocalSpringSliderDashpot_H
+#define WallLocalSpringSliderDashpot_H
+
+#include "WallModel.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+/*---------------------------------------------------------------------------*\
+                Class WallLocalSpringSliderDashpot Declaration
+\*---------------------------------------------------------------------------*/
+
+template<class CloudType>
+class WallLocalSpringSliderDashpot
+:
+    public WallModel<CloudType>
+{
+    // Private data
+
+        //- Effective Young's modulus value
+        scalarList Estar_;
+
+        //- Effective shear modulus value
+        scalarList Gstar_;
+
+        //- alpha-coefficient, related to coefficient of restitution
+        scalarList alpha_;
+
+        //- Spring power (b = 1 for linear, b = 3/2 for Hertzian)
+        scalarList b_;
+
+        //- Coefficient of friction in for tangential sliding
+        scalarList mu_;
+
+        //- Mapping the patch index to the model data
+        labelList patchMap_;
+
+        //- Index of the maximum value of Estar_
+        label maxEstarIndex_;
+
+        //- The number of steps over which to resolve the minimum
+        //  harmonic approximation of the collision period
+        scalar collisionResolutionSteps_;
+
+        //- Volume factor for determining the equivalent size of a
+        //  parcel where nParticles is not 1.  The equivalent size of
+        //  the parcel is
+        //      parcelEquivVolume = volumeFactor*nParticles*p.volume()
+        //  so
+        //      parcelEquivD = cbrt(volumeFactor*nParticles)*p.d()
+        //  + When volumeFactor = 1, the particles are compressed
+        //    together so that the equivalent volume of the parcel is
+        //    the sum of the constituent particles
+        //  + When volumeFactor = 3*sqrt(2)/pi, the particles are
+        //    close packed, but uncompressed.
+        //  + When volumeFactor > 3*sqrt(2)/pi, the particles loosely
+        //    grouped.
+        // 3*sqrt(2)/pi = 1.350474 is the volume factor for close
+        // packing, i.e pi/(3*sqrt(2)) is the maximum close packing
+        // factor
+        scalar volumeFactor_;
+
+        //- Switch to control use of equivalent size particles.  Used
+        //  because the calculation can be very expensive.
+        bool useEquivalentSize_;
+
+
+    // Private Member Functions
+
+        //- Find the appropriate properties for determining the minimum
+        //- allowable timestep
+        void findMinMaxProperties
+        (
+            scalar& rMin,
+            scalar& rhoMax,
+            scalar& vMagMax
+        ) const;
+
+        //- Calculate the wall interaction for a parcel at a given site
+        void evaluateWall
+        (
+            typename CloudType::parcelType& p,
+            const point& site,
+            const WallSiteData<vector>& data,
+            scalar pREff
+        ) const;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("WallLocalSpringSliderDashpot");
+
+
+    // Constructors
+
+        //- Construct from dictionary
+        WallLocalSpringSliderDashpot(const dictionary& dict, CloudType& cloud);
+
+
+    //- Destructor
+    virtual ~WallLocalSpringSliderDashpot();
+
+
+    // Member Functions
+
+        //- Return the volumeFactor
+        inline scalar volumeFactor() const
+        {
+            return volumeFactor_;
+        }
+
+        //- Return the effective radius for a particle for the model
+        virtual scalar pREff(const typename CloudType::parcelType& p) const;
+
+        //- Whether the WallModel has a timestep limit that will
+        //  require subCycling
+        virtual bool controlsTimestep() const;
+
+        //- For WallModels that control the timestep, calculate the
+        //  number of subCycles needed to satisfy the minimum
+        //  allowable timestep
+        virtual label nSubCycles() const;
+
+        //- Calculate the wall interaction for a parcel
+        virtual void evaluateWall
+        (
+            typename CloudType::parcelType& p,
+            const List<point>& flatSitePoints,
+            const List<WallSiteData<vector> >& flatSiteData,
+            const List<point>& sharpSitePoints,
+            const List<WallSiteData<vector> >& sharpSiteData
+        ) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#ifdef NoRepository
+#   include "WallLocalSpringSliderDashpot.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.C b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.C
index d8f1ffa84e..d25cc29c6a 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.C
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.C
@@ -58,6 +58,14 @@ Foam::WallModel<CloudType>::owner() const
 }
 
 
+template<class CloudType>
+CloudType&
+Foam::WallModel<CloudType>::owner()
+{
+    return owner_;
+}
+
+
 template<class CloudType>
 const Foam::dictionary& Foam::WallModel<CloudType>::dict() const
 {
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.H b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.H
index 31fde4e299..392825f829 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.H
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallModel/WallModel.H
@@ -111,6 +111,9 @@ public:
         //- Return the owner cloud object
         const CloudType& owner() const;
 
+        //- Return non-const access to the owner cloud object
+        CloudType& owner();
+
         //- Return the dictionary
         const dictionary& dict() const;
 
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.C b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.C
index b4b8262cbf..a2cc666f15 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.C
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.C
@@ -76,19 +76,15 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
     typename CloudType::parcelType& p,
     const point& site,
     const WallSiteData<vector>& data,
-    scalar pNu,
-    scalar pE,
     scalar pREff,
-    scalar Estar,
-    scalar kN,
-    scalar Gstar
+    scalar kN
 ) const
 {
     vector r_PW = p.position() - site;
 
     vector U_PW = p.U() - data.wallData();
 
-    scalar normalOverlapMag = pREff - mag(r_PW);
+    scalar normalOverlapMag = max(pREff - mag(r_PW), 0.0);
 
     vector rHat_PW = r_PW/(mag(r_PW) + VSMALL);
 
@@ -115,7 +111,7 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
 
     if (tangentialOverlapMag > VSMALL)
     {
-        scalar kT = 8.0*sqrt(pREff*normalOverlapMag)*Gstar;
+        scalar kT = 8.0*sqrt(pREff*normalOverlapMag)*Gstar_;
 
         scalar etaT = etaN;
 
@@ -156,8 +152,8 @@ Foam::WallSpringSliderDashpot<CloudType>::WallSpringSliderDashpot
 )
 :
     WallModel<CloudType>(dict, cloud, typeName),
-    E_(dimensionedScalar(this->coeffDict().lookup("youngsModulus")).value()),
-    nu_(dimensionedScalar(this->coeffDict().lookup("poissonsRatio")).value()),
+    Estar_(),
+    Gstar_(),
     alpha_(dimensionedScalar(this->coeffDict().lookup("alpha")).value()),
     b_(dimensionedScalar(this->coeffDict().lookup("b")).value()),
     mu_(dimensionedScalar(this->coeffDict().lookup("mu")).value()),
@@ -169,12 +165,30 @@ Foam::WallSpringSliderDashpot<CloudType>::WallSpringSliderDashpot
         )
     ),
     volumeFactor_(1.0),
-    useEquivalentSize_(Switch(this->dict().lookup("useEquivalentSize")))
+    useEquivalentSize_(Switch(this->coeffDict().lookup("useEquivalentSize")))
 {
     if (useEquivalentSize_)
     {
-        volumeFactor_ = readScalar(this->dict().lookup("volumeFactor"));
+        volumeFactor_ = readScalar(this->coeffDict().lookup("volumeFactor"));
     }
+
+    scalar nu = dimensionedScalar
+    (
+        this->coeffDict().lookup("poissonsRatio")
+    ).value();
+
+    scalar E = dimensionedScalar
+    (
+        this->coeffDict().lookup("youngsModulus")
+    ).value();
+
+    scalar pNu = this->owner().constProps().poissonsRatio();
+
+    scalar pE = this->owner().constProps().youngsModulus();
+
+    Estar_ = 1/((1 - sqr(pNu))/pE + (1 - sqr(nu))/E);
+
+    Gstar_ = 1/(2*((2 + pNu - sqr(pNu))/pE + (2 + nu - sqr(nu))/E));
 }
 
 
@@ -225,17 +239,11 @@ Foam::label Foam::WallSpringSliderDashpot<CloudType>::nSubCycles() const
 
     findMinMaxProperties(rMin, rhoMax, UMagMax);
 
-    scalar pNu = this->owner().constProps().poissonsRatio();
-
-    scalar pE = this->owner().constProps().youngsModulus();
-
-    scalar Estar = 1/((1 - sqr(pNu))/pE + (1 - sqr(nu_))/E_);
-
     // Note:  pi^(7/5)*(5/4)^(2/5) = 5.429675
     scalar minCollisionDeltaT =
         5.429675
        *rMin
-       *pow(rhoMax/(Estar*sqrt(UMagMax) + VSMALL), 0.4)
+       *pow(rhoMax/(Estar_*sqrt(UMagMax) + VSMALL), 0.4)
        /collisionResolutionSteps_;
 
     return ceil(this->owner().time().deltaTValue()/minCollisionDeltaT);
@@ -252,17 +260,9 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
     const List<WallSiteData<vector> >& sharpSiteData
 ) const
 {
-    scalar pNu = this->owner().constProps().poissonsRatio();
-
-    scalar pE = this->owner().constProps().youngsModulus();
-
     scalar pREff = this->pREff(p);
 
-    scalar Estar = 1/((1 - sqr(pNu))/pE + (1 - sqr(nu_))/E_);
-
-    scalar kN = (4.0/3.0)*sqrt(pREff)*Estar;
-
-    scalar GStar = 1/(2*((2 + pNu - sqr(pNu))/pE + (2 + nu_ - sqr(nu_))/E_));
+    scalar kN = (4.0/3.0)*sqrt(pREff)*Estar_;
 
     forAll(flatSitePoints, siteI)
     {
@@ -271,12 +271,8 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
             p,
             flatSitePoints[siteI],
             flatSiteData[siteI],
-            pNu,
-            pE,
             pREff,
-            Estar,
-            kN,
-            GStar
+            kN
         );
     }
 
@@ -289,12 +285,8 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
             p,
             sharpSitePoints[siteI],
             sharpSiteData[siteI],
-            pNu,
-            pE,
             pREff,
-            Estar,
-            kN,
-            GStar
+            kN
         );
     }
 }
diff --git a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.H b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.H
index 2c0d7461d9..e11ac0127a 100644
--- a/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.H
+++ b/src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.H
@@ -50,11 +50,11 @@ class WallSpringSliderDashpot
 {
     // Private data
 
-        //- Young's modulus of the wall
-        scalar E_;
+        //- Effective Young's modulus value
+        scalar Estar_;
 
-        //- Poisson's ratio of the wall
-        scalar nu_;
+        //- Effective shear modulus value
+        scalar Gstar_;
 
         //- alpha-coefficient, related to coefficient of restitution
         scalar alpha_;
@@ -109,12 +109,8 @@ class WallSpringSliderDashpot
             typename CloudType::parcelType& p,
             const point& site,
             const WallSiteData<vector>& data,
-            scalar pNu,
-            scalar pE,
             scalar pREff,
-            scalar Estar,
-            scalar kN,
-            scalar Gstar
+            scalar kN
         ) const;