diff options
Initialize at openlb-1-3
Diffstat (limited to 'src/dynamics/smagorinskyGuoZhaoDynamics.hh')
-rw-r--r-- | src/dynamics/smagorinskyGuoZhaoDynamics.hh | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/dynamics/smagorinskyGuoZhaoDynamics.hh b/src/dynamics/smagorinskyGuoZhaoDynamics.hh new file mode 100644 index 0000000..6a2ba73 --- /dev/null +++ b/src/dynamics/smagorinskyGuoZhaoDynamics.hh @@ -0,0 +1,118 @@ +/* This file is part of the OpenLB library + * + * Copyright (C) 2016-2017 Davide Dapelo, Mathias J. Krause + * OpenLB 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 + * Specific dynamics classes for Guo and Zhao (2002) porous model + * with a Smagorinsky LES turbulence model, with + * which a Cell object can be instantiated -- generic implementation. + */ +#ifndef LB_SMAGO_GUOZHAO_DYNAMICS_HH +#define LB_SMAGO_GUOZHAO_DYNAMICS_HH + +#include <algorithm> +#include <limits> +#include "dynamics/dynamics.h" +#include "core/cell.h" +#include "dynamics/guoZhaoLbHelpers.h" +#include "dynamics/firstOrderLbHelpers.h" + +namespace olb { + +////////////////////// Class SmagorinskyGuoZhaoBGKdynamics ///////////////////////// + +/** \param omega_ relaxation parameter, related to the dynamic viscosity + * \param momenta_ a Momenta object to know how to compute velocity momenta + */ +template<typename T, typename DESCRIPTOR> +SmagorinskyGuoZhaoBGKdynamics<T,DESCRIPTOR>::SmagorinskyGuoZhaoBGKdynamics (T omega_, + Momenta<T,DESCRIPTOR>& momenta_, T smagoConst_, T dx_, T dt_ ) + : GuoZhaoBGKdynamics<T,DESCRIPTOR>(omega_,momenta_), smagoConst(smagoConst_), + preFactor(computePreFactor(omega_,smagoConst_) ) +{ } + +template<typename T, typename DESCRIPTOR> +void SmagorinskyGuoZhaoBGKdynamics<T,DESCRIPTOR>::collide ( + Cell<T,DESCRIPTOR>& cell, + LatticeStatistics<T>& statistics ) +{ + // Copying epsilon from + // external to member variable to provide access for computeEquilibrium. + this->updateEpsilon(cell); + 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); + T* force = cell.template getFieldPointer<descriptors::FORCE>(); + for (int iVel=0; iVel<DESCRIPTOR::d; ++iVel) { + u[iVel] += force[iVel] / (T)2.; + } + T uSqr = GuoZhaoLbHelpers<T,DESCRIPTOR>::bgkCollision(cell, this->getEpsilon(), rho, u, newOmega); + GuoZhaoLbHelpers<T,DESCRIPTOR>::updateGuoZhaoForce(cell, u); + lbHelpers<T,DESCRIPTOR>::addExternalForce(cell, u, newOmega, rho); + statistics.incrementStats(rho, uSqr); +} + +template<typename T, typename DESCRIPTOR> +T SmagorinskyGuoZhaoBGKdynamics<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 SmagorinskyGuoZhaoBGKdynamics<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> +void SmagorinskyGuoZhaoBGKdynamics<T,DESCRIPTOR>::setOmega(T omega) +{ +// _omega = omega; + GuoZhaoBGKdynamics<T,DESCRIPTOR>::setOmega(omega); + preFactor = computePreFactor(omega, smagoConst); +} + +template<typename T, typename DESCRIPTOR> +T SmagorinskyGuoZhaoBGKdynamics<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; +} + +} + +#endif |