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ENH: Adding wall cohesion forces.

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This commit is contained in:
graham 2011-07-04 11:17:13 +01:00
parent 66ce33f53e
commit 5cad5dd91b
7 changed files with 86 additions and 17 deletions
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3
src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/PairModel/PairSpringSliderDashpot/PairSpringSliderDashpot.C
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@ -214,7 +214,8 @@ void Foam::PairSpringSliderDashpot<CloudType>::evaluatePair
rHat_AB
*(kN*pow(normalOverlapMag, b_) - etaN*(U_AB & rHat_AB));
// Cohesion force
// Cohesion force, energy density multiplied by the area of
// particle-particle overlap
if (cohesion_)
{
fN_AB +=

42
src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.C
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@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2008-2010 OpenCFD Ltd.
\\ / A nd | Copyright (C) 2008-2011 OpenCFD Ltd.
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -76,7 +76,8 @@ void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
typename CloudType::parcelType& p,
const point& site,
const WallSiteData<vector>& data,
scalar pREff
scalar pREff,
bool cohesion
) const
{
// wall patch index
@ -88,14 +89,18 @@ void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
scalar alpha = alpha_[wPI];
scalar b = b_[wPI];
scalar mu = mu_[wPI];
scalar cohesionEnergyDensity = cohesionEnergyDensity_[wPI];
cohesion = cohesion && cohesion_[wPI];
vector r_PW = p.position() - site;
vector U_PW = p.U() - data.wallData();
scalar normalOverlapMag = max(pREff - mag(r_PW), 0.0);
scalar r_PW_mag = mag(r_PW);
vector rHat_PW = r_PW/(mag(r_PW) + VSMALL);
scalar normalOverlapMag = max(pREff - r_PW_mag, 0.0);
vector rHat_PW = r_PW/(r_PW_mag + VSMALL);
scalar kN = (4.0/3.0)*sqrt(pREff)*Estar;
@ -105,6 +110,16 @@ void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
rHat_PW
*(kN*pow(normalOverlapMag, b) - etaN*(U_PW & rHat_PW));
// Cohesion force, energy density multiplied by the area of wall/particle
// overlap
if (cohesion)
{
fN_PW +=
-cohesionEnergyDensity
*mathematical::pi*(sqr(pREff) - sqr(r_PW_mag))
*rHat_PW;
}
p.f() += fN_PW;
vector USlip_PW =
@ -168,6 +183,8 @@ Foam::WallLocalSpringSliderDashpot<CloudType>::WallLocalSpringSliderDashpot
alpha_(),
b_(),
mu_(),
cohesionEnergyDensity_(),
cohesion_(),
patchMap_(),
maxEstarIndex_(-1),
collisionResolutionSteps_
@ -212,6 +229,8 @@ Foam::WallLocalSpringSliderDashpot<CloudType>::WallLocalSpringSliderDashpot
alpha_.setSize(nWallPatches);
b_.setSize(nWallPatches);
mu_.setSize(nWallPatches);
cohesionEnergyDensity_.setSize(nWallPatches);
cohesion_.setSize(nWallPatches);
scalar maxEstar = -GREAT;
@ -238,6 +257,13 @@ Foam::WallLocalSpringSliderDashpot<CloudType>::WallLocalSpringSliderDashpot
mu_[wPI] = readScalar(patchCoeffDict.lookup("mu"));
cohesionEnergyDensity_[wPI] = readScalar
(
patchCoeffDict.lookup("cohesionEnergyDensity")
);
cohesion_[wPI] = (mag(cohesionEnergyDensity_[wPI]) > VSMALL);
if (Estar_[wPI] > maxEstar)
{
maxEstarIndex_ = wPI;
@ -325,20 +351,22 @@ void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall
p,
flatSitePoints[siteI],
flatSiteData[siteI],
pREff
pREff,
true
);
}
forAll(sharpSitePoints, siteI)
{
// Treating sharp sites like flat sites
// Treating sharp sites like flat sites, except suppress cohesion
evaluateWall
(
p,
sharpSitePoints[siteI],
sharpSiteData[siteI],
pREff
pREff,
false
);
}
}

9
src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallLocalSpringSliderDashpot/WallLocalSpringSliderDashpot.H
View File

@ -65,6 +65,12 @@ class WallLocalSpringSliderDashpot
//- Coefficient of friction in for tangential sliding
scalarList mu_;
//- Cohesion energy density [J/m^3]
scalarList cohesionEnergyDensity_;
// Switch cohesion on and off
boolList cohesion_;
//- Mapping the patch index to the model data
labelList patchMap_;
@ -115,7 +121,8 @@ class WallLocalSpringSliderDashpot
typename CloudType::parcelType& p,
const point& site,
const WallSiteData<vector>& data,
scalar pREff
scalar pREff,
bool cohesion
) const;

36
src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.C
View File

@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2008-2010 OpenCFD Ltd.
\\ / A nd | Copyright (C) 2008-2011 OpenCFD Ltd.
\\/ M anipulation |
-------------------------------------------------------------------------------
License
@ -77,16 +77,19 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
const point& site,
const WallSiteData<vector>& data,
scalar pREff,
scalar kN
scalar kN,
bool cohesion
) const
{
vector r_PW = p.position() - site;
vector U_PW = p.U() - data.wallData();
scalar normalOverlapMag = max(pREff - mag(r_PW), 0.0);
scalar r_PW_mag = mag(r_PW);
vector rHat_PW = r_PW/(mag(r_PW) + VSMALL);
scalar normalOverlapMag = max(pREff - r_PW_mag, 0.0);
vector rHat_PW = r_PW/(r_PW_mag + VSMALL);
scalar etaN = alpha_*sqrt(p.mass()*kN)*pow025(normalOverlapMag);
@ -94,6 +97,16 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
rHat_PW
*(kN*pow(normalOverlapMag, b_) - etaN*(U_PW & rHat_PW));
// Cohesion force, energy density multiplied by the area of wall/particle
// overlap
if (cohesion)
{
fN_PW +=
-cohesionEnergyDensity_
*mathematical::pi*(sqr(pREff) - sqr(r_PW_mag))
*rHat_PW;
}
p.f() += fN_PW;
vector USlip_PW =
@ -157,6 +170,11 @@ Foam::WallSpringSliderDashpot<CloudType>::WallSpringSliderDashpot
alpha_(readScalar(this->coeffDict().lookup("alpha"))),
b_(readScalar(this->coeffDict().lookup("b"))),
mu_(readScalar(this->coeffDict().lookup("mu"))),
cohesionEnergyDensity_
(
readScalar(this->coeffDict().lookup("cohesionEnergyDensity"))
),
cohesion_(false),
collisionResolutionSteps_
(
readScalar
@ -183,6 +201,8 @@ Foam::WallSpringSliderDashpot<CloudType>::WallSpringSliderDashpot
Estar_ = 1/((1 - sqr(pNu))/pE + (1 - sqr(nu))/E);
Gstar_ = 1/(2*((2 + pNu - sqr(pNu))/pE + (2 + nu - sqr(nu))/E));
cohesion_ = (mag(cohesionEnergyDensity_) > VSMALL);
}
@ -266,13 +286,14 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
flatSitePoints[siteI],
flatSiteData[siteI],
pREff,
kN
kN,
cohesion_
);
}
forAll(sharpSitePoints, siteI)
{
// Treating sharp sites like flat sites
// Treating sharp sites like flat sites, except suppress cohesion
evaluateWall
(
@ -280,7 +301,8 @@ void Foam::WallSpringSliderDashpot<CloudType>::evaluateWall
sharpSitePoints[siteI],
sharpSiteData[siteI],
pREff,
kN
kN,
false
);
}
}

9
src/lagrangian/intermediate/submodels/Kinematic/CollisionModel/PairCollision/WallModel/WallSpringSliderDashpot/WallSpringSliderDashpot.H
View File

@ -65,6 +65,12 @@ class WallSpringSliderDashpot
//- Coefficient of friction in for tangential sliding
scalar mu_;
//- Cohesion energy density [J/m^3]
scalar cohesionEnergyDensity_;
// Switch cohesion on and off
bool cohesion_;
//- The number of steps over which to resolve the minimum
// harmonic approximation of the collision period
scalar collisionResolutionSteps_;
@ -110,7 +116,8 @@ class WallSpringSliderDashpot
const point& site,
const WallSiteData<vector>& data,
scalar pREff,
scalar kN
scalar kN,
bool cohesion
) const;

2
tutorials/lagrangian/icoUncoupledKinematicParcelFoam/hopper/hopperEmptying/constant/kinematicCloudProperties
View File

@ -112,6 +112,7 @@ subModels
alpha 0.12;
b 1.5;
mu 0.43;
cohesionEnergyDensity 0;
}
frontAndBack
{
@ -120,6 +121,7 @@ subModels
alpha 0.12;
b 1.5;
mu 0.1;
cohesionEnergyDensity 0;
}
};
}

2
tutorials/lagrangian/icoUncoupledKinematicParcelFoam/hopper/hopperInitialState/constant/kinematicCloudProperties
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@ -121,6 +121,7 @@ subModels
alpha 0.12;
b 1.5;
mu 0.43;
cohesionEnergyDensity 0;
}
frontAndBack
{
@ -129,6 +130,7 @@ subModels
alpha 0.12;
b 1.5;
mu 0.1;
cohesionEnergyDensity 0;
}
};
}