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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_POROUS_BGK_DYNAMICS_HH
#define SMAGORINSKY_POWER_LAW_POROUS_BGK_DYNAMICS_HH
#include "SmagorinskyPowerLawPorousBGKdynamics.h"
#include "SmagorinskyPorousParticleBGKdynamics.hh"
#include "math.h"
namespace olb {
////////////////////// Class SmagorinskyPowerLawPorousParticleBGKdynamics //////////////////////////
/** \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>
SmagorinskyPowerLawPorousParticleBGKdynamics<T,DESCRIPTOR>::SmagorinskyPowerLawPorousParticleBGKdynamics (
T omega_, Momenta<T,DESCRIPTOR>& momenta_, T m_, T n_ , T dtPL_, T nuMin, T nuMax, T smagoConst_)
: SmagorinskyPorousParticleBGKdynamics<T,DESCRIPTOR>(omega_,momenta_,smagoConst_),
m(m_),
n(n_),
dtPL(dtPL_)
//preFactor(computePreFactor(omega_,smagoConstPL_) )
{
omegaMin = 2./(nuMax*2.*descriptors::invCs2<T,DESCRIPTOR>() + 1.);
omegaMax = 2./(nuMin*2.*descriptors::invCs2<T,DESCRIPTOR>() + 1.);
}
template<typename T, typename DESCRIPTOR>
void SmagorinskyPowerLawPorousParticleBGKdynamics<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);
// load old omega from dyn. omega descriptor
// T oldOmega = this->getOmega(); //compute with constant omega
T oldOmega = cell.template getFieldPointer<descriptors::OMEGA>()[0]; //compute with dynamic omega
T OmegaPL = computeOmegaPL(oldOmega, rho, pi);
T* velDenominator = cell.template getFieldPointer<descriptors::VELOCITY_DENOMINATOR>();
T* velNumerator = cell.template getFieldPointer<descriptors::VELOCITY_NUMERATOR>();
T* porosity = cell.template getFieldPointer<descriptors::POROSITY>();
if (*velDenominator > std::numeric_limits<T>::epsilon()) {
*porosity = 1.-*porosity; // 1-prod(1-smoothInd)
for (int i=0; i < DESCRIPTOR::d; i++) {
u[i] += *porosity * (*(velNumerator+i) / *velDenominator - u[i]);
}
}
T newOmega = this->computeOmega(OmegaPL, this->preFactor, rho, pi);
T uSqr = lbHelpers<T,DESCRIPTOR>::bgkCollision(cell, rho, u, newOmega);
// save new omega to dyn. omega descriptor
cell.template getFieldPointer<descriptors::OMEGA>()[0] = newOmega; //compute with dynamic omega
statistics.incrementStats(rho, uSqr);
cell.template defineField<descriptors::POROSITY>(1.0);
cell.template defineField<descriptors::VELOCITY_DENOMINATOR>(0.0);
cell.template defineField<descriptors::VELOCITY_NUMERATOR>(0.0);
}
template<typename T, typename DESCRIPTOR>
T SmagorinskyPowerLawPorousParticleBGKdynamics<T,DESCRIPTOR>::computeOmegaPL(T omega0, T rho, T pi[util::TensorVal<DESCRIPTOR >::n] )
{
// strain rate tensor without prefactor
T PiNeqNormSqr = pi[0]*pi[0] + 2.*pi[1]*pi[1] + pi[2]*pi[2];
if (util::TensorVal<DESCRIPTOR >::n == 6) {
PiNeqNormSqr += pi[2]*pi[2] + pi[3]*pi[3] + 2.*pi[4]*pi[4] +pi[5]*pi[5];
}
T pre2 = pow(descriptors::invCs2<T,DESCRIPTOR>()/2./dtPL* omega0/rho,2.); // prefactor to the strain rate tensor
T D = pre2*PiNeqNormSqr; // Strain rate tensor
T gamma = sqrt(2.*D); // shear rate
T nuNew = m*pow(gamma,n-1.); //nu for non-Newtonian fluid
//T newOmega = 2./(nuNew*6.+1.);
T newOmega = 2./(nuNew*2.*descriptors::invCs2<T,DESCRIPTOR>() + 1.);
/*
* problem if newOmega too small or too big is see e.g. "Daniel Conrad , Andreas Schneider, Martin Böhle:
* A viscosity adaption method for Lattice Boltzmann simulations"
*/
//if (newOmega>1.965) {
// newOmega = 1.965; //std::cout << newOmega << std::endl;
//}
//if (newOmega<0.1) {
// newOmega = 0.1; //std::cout << newOmega << std::endl;
//}
if (newOmega>omegaMax) {
newOmega = omegaMax; //std::cout << newOmega << std::endl;
}
if (newOmega<omegaMin) {
newOmega = omegaMin; //std::cout << newOmega << std::endl;
}
// std::cout << newOmega << std::endl;
return newOmega;
//return omega0;
}
}
#endif
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