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Extended Beestra drag model to polydisperse particles, correction in the superficial velocity (voidfraction*Uf-Us instead uf voidfraction(Uf-Us))

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This commit is contained in:
s126103
2018-05-17 10:40:31 +02:00
parent dd611fc7a0
commit 9051bb7a70
3 changed files with 72 additions and 33 deletions
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97
src/lagrangian/cfdemParticle/subModels/forceModel/BeetstraDrag/BeetstraDrag.C
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@ -56,12 +56,24 @@ BeetstraDrag::BeetstraDrag
UsFieldName_(propsDict_.lookup("granVelFieldName")),
UsField_(sm.mesh().lookupObject<volVectorField> (UsFieldName_)),
scaleDia_(1.),
scaleDrag_(1.)
scaleDrag_(1.),
polydisperse_(false),
dSauterFieldName_(propsDict_.lookup("dSauterFieldName")),
dSauterField_(sm.mesh().lookupObject<volScalarField> (dSauterFieldName_))
{
if(propsDict_.found("polydisperse"))
{
polydisperse_ = readBool(propsDict_.lookup("polydisperse"));
if(polydisperse_)
{
Info << "Drag model: using polydisperse correction factor \n";
}
}
//Append the field names to be probed
particleCloud_.probeM().initialize(typeName, typeName+".logDat");
particleCloud_.probeM().vectorFields_.append("dragForce"); //first entry must be the force
particleCloud_.probeM().vectorFields_.append("Urel");
particleCloud_.probeM().vectorFields_.append("Urelsup");
particleCloud_.probeM().scalarFields_.append("Rep");
particleCloud_.probeM().scalarFields_.append("betaP");
particleCloud_.probeM().scalarFields_.append("voidfraction");
@ -112,35 +124,41 @@ void BeetstraDrag::setForce() const
vector position(0,0,0);
scalar voidfraction(1);
vector Ufluid(0,0,0);
vector Ufluidsup(0,0,0);
vector drag(0,0,0);
label cellI=0;
label cellI = 0;
vector Us(0,0,0);
vector Ur(0,0,0);
vector Ursup(0,0,0);
scalar ds(0);
scalar ds_scaled(0);
scalar scaleDia3 = scaleDia_*scaleDia_*scaleDia_;
scalar nuf(0);
scalar rho(0);
scalar magUr(0);
scalar magUrsup(0);
scalar Rep(0);
scalar localPhiP(0);
scalar Fdrag(0);
scalar yi(0);
scalar dSauter(0);
vector dragExplicit(0,0,0);
scalar dragCoefficient(0);
interpolationCellPoint<scalar> voidfractionInterpolator_(voidfraction_);
interpolationCellPoint<scalar> dSauterInterpolator_(dSauterField_);
interpolationCellPoint<vector> UInterpolator_(U_);
#include "setupProbeModel.H"
for(int index = 0; index < particleCloud_.numberOfParticles(); ++index)
{
cellI = particleCloud_.cellIDs()[index][0];
drag = vector(0,0,0);
dragExplicit = vector(0,0,0);
Ufluid =vector(0,0,0);
voidfraction=0;
cellI = particleCloud_.cellIDs()[index][0];
drag = vector(0,0,0);
dragExplicit = vector(0,0,0);
Ufluid = vector(0,0,0);
Ufluidsup = vector(0,0,0);
voidfraction = 0;
dragCoefficient = 0;
if (cellI > -1) // particle found
@ -154,7 +172,7 @@ void BeetstraDrag::setForce() const
//Ensure interpolated void fraction to be meaningful
// Info << " --> voidfraction: " << voidfraction << endl;
if(voidfraction>1.00) voidfraction = 1.0;
if(voidfraction<0.10) voidfraction = 0.10;
if(voidfraction<0.30) voidfraction = 0.30;
}
else
{
@ -162,41 +180,56 @@ void BeetstraDrag::setForce() const
Ufluid = U_[cellI];
}
Us = particleCloud_.velocity(index);
Ur = Ufluid-Us;
magUr = mag(Ur);
ds = 2*particleCloud_.radius(index);
ds_scaled = ds/scaleDia_;
rho = rhoField[cellI];
nuf = nufField[cellI];
Ufluidsup = Ufluid*voidfraction;
Us = particleCloud_.velocity(index);
Ursup = Ufluidsup-Us;
magUrsup = mag(Ursup);
ds = 2*particleCloud_.radius(index);
ds_scaled = ds/scaleDia_;
rho = rhoField[cellI];
nuf = nufField[cellI];
localPhiP = 1.0f-voidfraction+SMALL;
Rep=0.0;
localPhiP = 1.0f-voidfraction+SMALL;
// Ur is interstitial velocity, Beetstra uses superficial!
Rep = ds_scaled*magUrsup/nuf+SMALL;
// calc particle's drag coefficient (i.e., Force per unit slip velocity and Stokes drag)
// Beetstra et. al (2007), Eq. (21)
Fdrag = 10.0*localPhiP/(voidfraction*voidfraction)
+ voidfraction*voidfraction*(1.0+1.5*sqrt(localPhiP))
+ 0.413*Rep/(24*voidfraction*voidfraction)
* (1.0/voidfraction + 3*voidfraction*localPhiP + 8.4*pow(Rep,-0.343))
/ (1+pow(10,3*localPhiP)*pow(Rep,-0.5*(1+4*localPhiP)));
Rep=ds_scaled*voidfraction*magUr/nuf+SMALL;
dragCoefficient = 10.0*localPhiP/(voidfraction*voidfraction) +
voidfraction*voidfraction*(1.0+1.5*Foam::sqrt(localPhiP)) +
0.413*Rep/(24*voidfraction*voidfraction)*(1.0/voidfraction+3*voidfraction*localPhiP+8.4*Foam::pow(Rep,-0.343))/
(1+Foam::pow(10,3*localPhiP)*Foam::pow(Rep,-0.5*(1+4*localPhiP)));
if (polydisperse_)
{
if( forceSubM(0).interpolation() )
dSauter = dSauterInterpolator_.interpolate(position,cellI);
else
dSauter = dSauterField_[cellI];
// Beetstra et. al (2007), Eq. (21)
yi = ds_scaled/dSauter;
Fdrag *= (voidfraction*yi + localPhiP*yi*yi + 0.064*voidfraction*yi*yi*yi);
}
// calc particle's drag
dragCoefficient *= 3*M_PI*ds_scaled*nuf*rho*voidfraction*scaleDia3*scaleDrag_;
dragCoefficient = Fdrag*3.0*M_PI*ds_scaled*nuf*rho*scaleDrag_*scaleDia3;
if (modelType_=="B")
dragCoefficient /= voidfraction;
drag = dragCoefficient * Ur;
drag = dragCoefficient * Ursup;
// explicitCorr
forceSubM(0).explicitCorr(drag,dragExplicit,dragCoefficient,Ufluid,U_[cellI],Us,UsField_[cellI],forceSubM(0).verbose());
forceSubM(0).explicitCorr(drag,dragExplicit,dragCoefficient,Ufluidsup,U_[cellI]*voidfraction_[cellI],Us,UsField_[cellI],forceSubM(0).verbose());
if(forceSubM(0).verbose() && index >=0 && index <2)
{
Pout << "cellI = " << cellI << endl;
Pout << "index = " << index << endl;
Pout << "Ufluidsup = " << Ufluidsup << endl;
Pout << "Us = " << Us << endl;
Pout << "Ur = " << Ur << endl;
Pout << "Ursup = " << Ursup << endl;
Pout << "ds = " << ds << endl;
Pout << "ds/scale = " << ds/scaleDia_ << endl;
Pout << "rho = " << rho << endl;
@ -211,7 +244,7 @@ void BeetstraDrag::setForce() const
{
#include "setupProbeModelfields.H"
vValues.append(drag); //first entry must the be the force
vValues.append(Ur);
vValues.append(Ursup);
sValues.append(Rep);
sValues.append(voidfraction);
particleCloud_.probeM().writeProbe(index, sValues, vValues);
@ -219,7 +252,7 @@ void BeetstraDrag::setForce() const
}
// write particle based data to global array
forceSubM(0).partToArray(index,drag,dragExplicit,Ufluid,dragCoefficient);
forceSubM(0).partToArray(index,drag,dragExplicit,Ufluidsup,dragCoefficient);
}
}

6
src/lagrangian/cfdemParticle/subModels/forceModel/BeetstraDrag/BeetstraDrag.H
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@ -59,6 +59,12 @@ private:
mutable scalar scaleDrag_;
mutable bool polydisperse_;
word dSauterFieldName_;
const volScalarField& dSauterField_;
public:
//- Runtime type information

2
src/lagrangian/cfdemParticle/subModels/forceModel/virtualMassForce/virtualMassForce.C
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@ -69,7 +69,7 @@ virtualMassForce::virtualMassForce
U_(sm.mesh().lookupObject<volVectorField> (velFieldName_)),
voidfractionFieldName_(propsDict_.lookup("voidfractionFieldName")),
voidfraction_(sm.mesh().lookupObject<volScalarField> (voidfractionFieldName_)),
UsFieldName_(propsDict_.lookup("UsFieldName")),
UsFieldName_(propsDict_.lookup("granVelFieldName")),
Us_(sm.mesh().lookupObject<volVectorField> (UsFieldName_)),
phiFieldName_(propsDict_.lookup("phiFieldName")),
phi_(sm.mesh().lookupObject<surfaceScalarField> (phiFieldName_)),