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/* This file is part of the OpenLB library
*
* Copyright (C) 2016 Thomas Henn
* E-mail contact: info@openlb.net
* The most recent release of OpenLB can be downloaded at
* <http://www.openlb.net/>
*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef STOKESDRAGFORCE_3D_HH
#define STOKESDRAGFORCE_3D_HH
#include<cmath>
#include "stokesDragForce3D.h"
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
namespace olb {
template<typename T, template<typename U> class PARTICLETYPE, typename DESCRIPTOR>
StokesDragForce3D<T, PARTICLETYPE, DESCRIPTOR>::StokesDragForce3D(SuperLatticeInterpPhysVelocity3D<T, DESCRIPTOR>& getVel, T dT, T mu)
: Force3D<T, PARTICLETYPE>(),
_getVel(getVel),
_mu(mu)
{
_C1 = 6. * M_PI * _mu * dT ;
_dTinv = 1. / dT;
_scaleFactor = 1.;
}
template<typename T, template<typename U> class PARTICLETYPE, typename DESCRIPTOR>
StokesDragForce3D<T, PARTICLETYPE, DESCRIPTOR>::StokesDragForce3D(SuperLatticeInterpPhysVelocity3D<T, DESCRIPTOR>& getVel, UnitConverter<T, DESCRIPTOR> const& converter)
: Force3D<T, PARTICLETYPE>(),
_getVel(getVel)
{
//implicit formulation
_C1 = 6. * M_PI * converter.getPhysViscosity() * converter.getPhysDensity() * converter.getConversionFactorTime();
_mu = converter.getPhysViscosity() * converter.getPhysDensity();
// explicit formulation
// _C1 = 6. * M_PI * converter.getDynamicViscosity();
_dTinv = 1. / converter.getConversionFactorTime();
_scaleFactor = 1. ;
}
template<typename T, template<typename U> class PARTICLETYPE, typename DESCRIPTOR>
StokesDragForce3D<T, PARTICLETYPE, DESCRIPTOR>::StokesDragForce3D(SuperLatticeInterpPhysVelocity3D<T, DESCRIPTOR>& getVel, UnitConverter<T, DESCRIPTOR> const& converter, T scaleFactor)
: Force3D<T, PARTICLETYPE>(),
_getVel(getVel),
_scaleFactor(scaleFactor)
{
//implicit formulation
_C1 = 6. * M_PI * converter.getPhysViscosity() * converter.getPhysDensity() * converter.getConversionFactorTime();
_mu = converter.getPhysViscosity() * converter.getPhysDensity();
// explicit formulation
// _C1 = 6. * M_PI * converter.getDynamicViscosity();
_dTinv = 1. / converter.getConversionFactorTime();
}
/// 6 Pi r mu (u_f-u_p)
template<typename T, template<typename U> class PARTICLETYPE, typename DESCRIPTOR>
void StokesDragForce3D<T, PARTICLETYPE, DESCRIPTOR>::applyForce(
typename std::deque<PARTICLETYPE<T> >::iterator p, int pInt,
ParticleSystem3D<T, PARTICLETYPE>& psSys)
{
T fluidVel[3] = {0., 0., 0.};
//implicit formulation
_getVel(fluidVel, &p->getPos()[0], p->getCuboid());
fluidVel[0] *= _scaleFactor;
fluidVel[1] *= _scaleFactor;
fluidVel[2] *= _scaleFactor;
T c = _C1 * p->getRad() * p->getInvMass();
T C2 = 1. / (1. + c);
// p->getVel() is particle velocity of the last time step
// formulation of new force with particle velocity of the last time step with
// implicit Euler
p->getForce()[0] += p->getMass() * _dTinv
* ((c * fluidVel[0] + p->getVel()[0]) * C2 - p->getVel()[0]);
p->getForce()[1] += p->getMass() * _dTinv
* ((c * fluidVel[1] + p->getVel()[1]) * C2 - p->getVel()[1]);
p->getForce()[2] += p->getMass() * _dTinv
* ((c * fluidVel[2] + p->getVel()[2]) * C2 - p->getVel()[2]);
// explicit formulation
// T cex = 6. * M_PI * _mu * p->getRad();
// p->getForce()[0] += cex * (fluidVel[0]-p->getVel()[0]);
// p->getForce()[1] += cex * (fluidVel[1]-p->getVel()[1]);
// p->getForce()[2] += cex * (fluidVel[2]-p->getVel()[2]);
}
template<typename T, template<typename U> class PARTICLETYPE, typename DESCRIPTOR>
void StokesDragForce3D<T, PARTICLETYPE, DESCRIPTOR>::computeForce(
int pInt, ParticleSystem3D<T, PARTICLETYPE>* psSys, T force[3])
{
T fluidVel[3] = {0., 0., 0.};
_getVel(fluidVel, &psSys->operator[](pInt).getPos()[0], psSys->operator[](pInt).getCuboid());
T c = _C1 * psSys->operator[](pInt).getRad() * psSys->operator[](pInt).getInvMass();
T C2 = 1. / (1. + c);
T mass = psSys->operator[](pInt).getMass();
std::vector<T> vel = psSys->operator[](pInt).getVel();
force[0] = mass * _dTinv * ((c * fluidVel[0] + vel[0]) * C2 - vel[0]);
force[1] = mass * _dTinv * ((c * fluidVel[1] + vel[1]) * C2 - vel[1]);
force[2] = mass * _dTinv * ((c * fluidVel[2] + vel[2]) * C2 - vel[2]);
}
}
#endif /* STOKESDRAGFORCE_3D_HH */
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