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/* This file is part of the OpenLB library
*
* Copyright (C) 2012, 2015 Mathias J. Krause, Vojtech Cvrcekt, Davide Dapelo
* 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.
*/
/** \file
* Porous-particle BGK Dynamics with adjusted omega
* and Smagorinsky turbulence model -- generic implementation.
* Strain rate similar to "J.Boyd, J. Buick and S.Green: A second-order accurate lattice Boltzmann non-Newtonian flow model"
* Power Law similar to "Huidan Yu, Sharath S. Girimaji, Li-Shi Luo - DNS and LES of decaying isotropic turbulence with and without frame rotation using lattice Boltzmann method"
*/
#ifndef SMAGORINSKY_POWER_LAW_BGK_DYNAMICS_HH
#define SMAGORINSKY_POWER_LAW_BGK_DYNAMICS_HH
#include "../dynamics/powerLawBGKdynamics.h"
#include "SmagorinskyPowerLawBGKdynamics.h"
#include "math.h"
namespace olb {
////////////////////// Class SmagorinskyPowerLawBGKdynamics //////////////////////////
/** \param vs2_ speed of sound
* \param momenta_ a Momenta object to know how to compute velocity momenta
* \param momenta_ a Momenta object to know how to compute velocity momenta
*/
template<typename T, typename DESCRIPTOR>
SmagorinskyPowerLawBGKdynamics<T,DESCRIPTOR>::SmagorinskyPowerLawBGKdynamics (
T omega, Momenta<T,DESCRIPTOR>& momenta, T m, T n , T nuMin, T nuMax, T smagoConst)
: SmagorinskyBGKdynamics<T,DESCRIPTOR>(omega, momenta, smagoConst),
PowerLawDynamics<T,DESCRIPTOR>(m, n, nuMin, nuMax)
{ }
template<typename T, typename DESCRIPTOR>
void SmagorinskyPowerLawBGKdynamics<T,DESCRIPTOR>::collide (
Cell<T,DESCRIPTOR>& cell,
LatticeStatistics<T>& statistics )
{
T rho, u[DESCRIPTOR::d], pi[util::TensorVal<DESCRIPTOR >::n];
this->_momenta.computeAllMomenta(cell, rho, u, pi);
// Computation of the power-law omega.
// An external is used in place of BGKdynamics::_omega to keep generality and flexibility.
T oldOmega = cell.template getFieldPointer<descriptors::OMEGA>()[0];
T intOmega = this->computeOmegaPL(cell, oldOmega, rho, pi);
T newOmega = computeEffectiveOmega(cell, intOmega); // turbulent omega
T uSqr = lbHelpers<T,DESCRIPTOR>::bgkCollision(cell, rho, u, newOmega);
cell.template getFieldPointer<descriptors::OMEGA>()[0] = intOmega; // updating omega
statistics.incrementStats(rho, uSqr);
}
template<typename T, typename DESCRIPTOR>
T SmagorinskyPowerLawBGKdynamics<T,DESCRIPTOR>::computeEffectiveOmega(Cell<T,DESCRIPTOR>& cell, T omega0)
{
T rho = this->_momenta.computeRho(cell);
T PiNeqNorm = sqrt(PiNeqNormSqr(cell));
/// Molecular realaxation time
T tau_mol = 1. /omega0;
/// Turbulent realaxation time
T tau_turb = 0.5*(sqrt(tau_mol*tau_mol + this->getPreFactor()/rho*PiNeqNorm) - tau_mol);
/// Effective realaxation time
T tau_eff = tau_mol+tau_turb;
T omega_new= 1./tau_eff;
return omega_new;
}
template<typename T, typename DESCRIPTOR>
T SmagorinskyPowerLawBGKdynamics<T,DESCRIPTOR>::PiNeqNormSqr(Cell<T,DESCRIPTOR>& cell )
{
return lbHelpers<T,DESCRIPTOR>::computePiNeqNormSqr(cell);
}
////////////////////// Class SmagorinskyPowerLawForcedBGKdynamics //////////////////////////
/** \param vs2_ speed of sound
* \param momenta_ a Momenta object to know how to compute velocity momenta
* \param momenta_ a Momenta object to know how to compute velocity momenta
*/
template<typename T, typename DESCRIPTOR>
SmagorinskyPowerLawForcedBGKdynamics<T,DESCRIPTOR>::SmagorinskyPowerLawForcedBGKdynamics (
T omega, Momenta<T,DESCRIPTOR>& momenta, T m, T n , T nuMin, T nuMax, T smagoConst)
: SmagorinskyForcedBGKdynamics<T,DESCRIPTOR>(omega, momenta, smagoConst),
PowerLawDynamics<T,DESCRIPTOR>(m, n, nuMin, nuMax)
{ }
template<typename T, typename DESCRIPTOR>
void SmagorinskyPowerLawForcedBGKdynamics<T,DESCRIPTOR>::collide (
Cell<T,DESCRIPTOR>& cell,
LatticeStatistics<T>& statistics )
{
T rho, u[DESCRIPTOR::d], pi[util::TensorVal<DESCRIPTOR >::n];
this->_momenta.computeAllMomenta(cell, rho, u, pi);
// Computation of the power-law omega.
// An external is used in place of BGKdynamics::_omega to keep generality and flexibility.
T oldOmega = cell.template getFieldPointer<descriptors::OMEGA>()[0];
T intOmega = this->computeOmegaPL(cell, oldOmega, rho, pi);
T newOmega = computeEffectiveOmega(cell, intOmega); // turbulent omega
T* force = cell.template getFieldPointer<descriptors::FORCE>();
for (int iVel=0; iVel<DESCRIPTOR::d; ++iVel) {
u[iVel] += force[iVel] / (T)2.;
}
T uSqr = lbHelpers<T,DESCRIPTOR>::bgkCollision(cell, rho, u, newOmega);
cell.template getFieldPointer<descriptors::OMEGA>()[0] = intOmega; // updating omega
lbHelpers<T,DESCRIPTOR>::addExternalForce(cell, u, newOmega, rho);
statistics.incrementStats(rho, uSqr);
}
template<typename T, typename DESCRIPTOR>
T SmagorinskyPowerLawForcedBGKdynamics<T,DESCRIPTOR>::computeEffectiveOmega(Cell<T,DESCRIPTOR>& cell, T omega0)
{
T rho = this->_momenta.computeRho(cell);
T PiNeqNorm = sqrt(PiNeqNormSqr(cell));
/// Molecular realaxation time
T tau_mol = 1. /omega0;
/// Turbulent realaxation time
T tau_turb = 0.5*(sqrt(tau_mol*tau_mol + this->getPreFactor()/rho*PiNeqNorm) - tau_mol);
/// Effective realaxation time
T tau_eff = tau_mol+tau_turb;
T omega_new= 1./tau_eff;
return omega_new;
}
template<typename T, typename DESCRIPTOR>
T SmagorinskyPowerLawForcedBGKdynamics<T,DESCRIPTOR>::PiNeqNormSqr(Cell<T,DESCRIPTOR>& cell )
{
return lbHelpers<T,DESCRIPTOR>::computeForcedPiNeqNormSqr(cell);
}
}
#endif
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