diff options
Diffstat (limited to 'src/dynamics/smagorinskyMRTdynamics.hh')
| -rw-r--r-- | src/dynamics/smagorinskyMRTdynamics.hh | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/src/dynamics/smagorinskyMRTdynamics.hh b/src/dynamics/smagorinskyMRTdynamics.hh new file mode 100644 index 0000000..45493f7 --- /dev/null +++ b/src/dynamics/smagorinskyMRTdynamics.hh @@ -0,0 +1,164 @@ +/* This file is part of the OpenLB library + * + * Copyright (C) 2012 Patrick Nathen, Mathias J. Krause + * 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 + * MRT Dynamics with adjusted omega -- generic implementation. + */ +#ifndef SMAGORINSKY_MRT_DYNAMICS_HH +#define SMAGORINSKY_MRT_DYNAMICS_HH + +#include <algorithm> +#include <limits> +#include "smagorinskyMRTdynamics.h" +#include "mrtDynamics.h" +#include "mrtHelpers.h" +#include "core/cell.h" +#include "core/util.h" +#include "math.h" + + +using namespace std; +namespace olb { + +////////////////////// Class SmagorinskyMRTdynamics ////////////////////////// + +/** \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> +SmagorinskyMRTdynamics<T,DESCRIPTOR>::SmagorinskyMRTdynamics ( + T omega_, Momenta<T,DESCRIPTOR>& momenta_, T smagoConst_, T dx_, T dt_ ) + : MRTdynamics<T,DESCRIPTOR>(omega_, momenta_/*, smagoConst_*/), + smagoConst(smagoConst_), + preFactor(computePreFactor(omega_,smagoConst_) ) +{ + + T rtSGS[DESCRIPTOR::q]; // relaxation times vector for SGS approach. + for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop) { + rtSGS[iPop] = DESCRIPTOR::S[iPop]; + } + for (int iPop = 0; iPop < DESCRIPTOR::shearIndexes; ++iPop) { + rtSGS[DESCRIPTOR::shearViscIndexes[iPop]] = omega; + } + for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop) { + for (int jPop = 0; jPop < DESCRIPTOR::q; ++jPop) { + invM_S_SGS[iPop][jPop] = T(); + for (int kPop = 0; kPop < DESCRIPTOR::q; ++kPop) { + if (kPop == jPop) { + invM_S_SGS[iPop][jPop] += DESCRIPTOR::invM[iPop][kPop] * rtSGS[kPop]; + } + } + } + } +} + + +template<typename T, typename DESCRIPTOR> +void SmagorinskyMRTdynamics<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); + T newOmega = computeOmega(this->getOmega(), preFactor, rho, pi); + for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop) { + for (int jPop = 0; jPop < DESCRIPTOR::shearIndexes; ++jPop) { + invM_S_SGS[iPop][DESCRIPTOR::shearViscIndexes[jPop]] = DESCRIPTOR::invM[iPop][DESCRIPTOR::shearViscIndexes[jPop]] * newOmega; + } + } + + T uSqr = mrtHelpers<T,DESCRIPTOR>::mrtSGSCollision(cell, rho, u, newOmega, invM_S_SGS); + statistics.incrementStats(rho, uSqr); +} + +template<typename T, typename DESCRIPTOR> +void SmagorinskyMRTdynamics<T,DESCRIPTOR>::setOmega(T omega) +{ + this->setOmega(omega); + preFactor = computePreFactor(omega, smagoConst); +} + +template<typename T, typename DESCRIPTOR> +T SmagorinskyMRTdynamics<T,DESCRIPTOR>::getSmagorinskyOmega(Cell<T,DESCRIPTOR>& cell ) +{ + T rho, uTemp[DESCRIPTOR::d], pi[util::TensorVal<DESCRIPTOR >::n]; + this->_momenta.computeAllMomenta(cell, rho, uTemp, pi); + T newOmega = computeOmega(this->getOmega(), preFactor, rho, pi); + return newOmega; +} + +template<typename T, typename DESCRIPTOR> +T SmagorinskyMRTdynamics<T,DESCRIPTOR>::computePreFactor(T omega, T smagoConst) +{ + return (T)smagoConst*smagoConst*descriptors::invCs2<T,DESCRIPTOR>()*descriptors::invCs2<T,DESCRIPTOR>()*2*sqrt(2); +} + +template<typename T, typename DESCRIPTOR> +T SmagorinskyMRTdynamics<T,DESCRIPTOR>::computeOmega(T omega0, T preFactor, T rho, T pi[util::TensorVal<DESCRIPTOR >::n] ) +{ + + T PiNeqNormSqr = pi[0]*pi[0] + 2.0*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 PiNeqNorm = sqrt(PiNeqNormSqr); + /// Molecular realaxation time + T tau_mol = 1. /omega0; + /// Turbulent realaxation time + T tau_turb = 0.5*(sqrt(tau_mol*tau_mol + preFactor/rho*PiNeqNorm) - tau_mol); + /// Effective realaxation time + tau_eff = tau_mol+tau_turb; + T omega_new= 1./tau_eff; + return omega_new; +} + + + +template<typename T, typename DESCRIPTOR> +void SmagorinskyForcedMRTdynamics<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); + T newOmega = computeOmega(this->getOmega(), this->preFactor, rho, pi); + for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop) { + for (int jPop = 0; jPop < DESCRIPTOR::shearIndexes; ++jPop) { + this->invM_S_SGS[iPop][DESCRIPTOR::shearViscIndexes[jPop]] = DESCRIPTOR::invM[iPop][DESCRIPTOR::shearViscIndexes[jPop]] * newOmega; + } + } + + T uSqr = mrtHelpers<T,DESCRIPTOR>::mrtSGSCollision(cell, rho, u, newOmega, this->invM_S_SGS); + + mrtHelpers<T,DESCRIPTOR>::addExternalForce(cell, rho, u, this->invM_S_SGS); + + statistics.incrementStats(rho, uSqr); +} + +} + +#endif |