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diff --git a/src/dynamics/SmagorinskyPowerLawBGKdynamics.hh b/src/dynamics/SmagorinskyPowerLawBGKdynamics.hh new file mode 100644 index 0000000..181f4d6 --- /dev/null +++ b/src/dynamics/SmagorinskyPowerLawBGKdynamics.hh @@ -0,0 +1,154 @@ +/* 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 |