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/* This file is part of the OpenLB library
*
* Copyright (C) 2018 Robin Trunk, Sam Avis
* 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.
*/
#ifndef FREE_ENERGY_DYNAMICS_H
#define FREE_ENERGY_DYNAMICS_H
#include "dynamics/dynamics.h"
/** \file
* In this file the dynamic calls for the free energy model is implemented. It
* is used for the second (and third) lattices, as for the first one a BGK collision with
* Guo forcing is applied (see ForcedBGKdynamcs).
*/
namespace olb {
template<typename T, typename DESCRIPTOR>
class FreeEnergyBGKdynamics : public BasicDynamics<T,DESCRIPTOR> {
public:
/// This dynamics describes the propagation of density(fluid1) - density(fluid2). And is
/// used for the second (and third) lattices in the free energy model.
/// \param[in] omega_ - lattice relaxation frequency [lattice units]
/// \param[in] gamma_ - tunable parameter for the equilibrium distribution [lattice units]
/// \param[in] momenta_ - momenta object describing the calculation of macroscopic values (e.g. rho and u).
/// Usually "BulkMomenta" are used.
FreeEnergyBGKdynamics(T omega_, T gamma_, Momenta<T,DESCRIPTOR>& momenta_);
/// Collision step
void collide(Cell<T,DESCRIPTOR>& cell,
LatticeStatistics<T>& statistics_) override;
/// Compute equilibrium distribution function.
/// This should contain an additional term that depends upon the chemical potential. However the external field
/// cannot be accessed when iniEquilibrium is called and so this has been neglected.
T computeEquilibrium(int iPop, T rho, const T u[DESCRIPTOR::d], T uSqr) const override;
/// Get local relaxation parameter of the dynamics
T getOmega() const override;
/// Set local relaxation parameter of the dynamics
void setOmega(T omega_) override;
/// Compute fluid velocity and particle density on the cell.
void computeRhoU(
Cell<T,DESCRIPTOR> const& cell,
T& rho, T u[DESCRIPTOR::d]) const override;
/// Compute fluid velocity on the cell.
void computeU(Cell<T,DESCRIPTOR> const& cell, T u[DESCRIPTOR::d]) const override;
private:
T omega; /// relaxation parameter
T gamma; /// tunable parameter
};
template<typename T, typename DESCRIPTOR>
class FreeEnergyWallDynamics : public BounceBack<T,DESCRIPTOR> {
public:
/// This dynamics is used for the second (and third) lattices in the free energy model at wall boundaries.
/// It is neccessary for returning the correct equilibrium distributions when iniEquilibrium is called.
FreeEnergyWallDynamics();
/// Compute equilibrium distribution function.
/// This should contain an additional term that depends upon the chemical potential. However the external field
/// cannot be accessed when iniEquilibrium is called and so this has been neglected.
T computeEquilibrium(int iPop, T rho, const T u[DESCRIPTOR::d], T uSqr) const override;
/// Get local relaxation parameter of the dynamics
T getOmega() const override;
/// Set local relaxation parameter of the dynamics
void setOmega(T omega_) override;
};
template<typename T, typename DESCRIPTOR, int direction, int orientation>
class FreeEnergyInletOutletDynamics : public BasicDynamics<T,DESCRIPTOR> {
public:
/// This dynamics is used for the second (and third) lattices in the free energy model at inlets.
/// It first defines the missing distribution functions and then performs the normal collision.
/// \param[in] omega_ - lattice relaxation frequency [lattice units]
/// \param[in] momenta_ - momenta object describing the calculation of macroscopic values (not including rho).
/// Usually "BulkMomenta" are used.
FreeEnergyInletOutletDynamics(T omega_, Momenta<T,DESCRIPTOR>& momenta_);
/// Collision step
void collide(Cell<T,DESCRIPTOR>& cell, LatticeStatistics<T>& statistics_) override;
/// Compute equilibrium distribution function.
/// This should contain an additional term that depends upon the chemical potential. However the external field
/// cannot be accessed when iniEquilibrium is called and so this has been neglected.
T computeEquilibrium(int iPop, T rho, const T u[DESCRIPTOR::d], T uSqr) const override;
/// Get local relaxation parameter of the dynamics
T getOmega() const override;
/// Set local relaxation parameter of the dynamics
void setOmega(T omega_) override;
/// Compute particle density on the cell.
T computeRho(Cell<T,DESCRIPTOR> const& cell) const override;
/// Compute fluid velocity on the cell.
void computeU(Cell<T,DESCRIPTOR > const &cell, T u[DESCRIPTOR::d]) const override;
/// Compute fluid velocity and particle density on the cell.
void computeRhoU (Cell<T,DESCRIPTOR> const& cell, T& rho, T u[DESCRIPTOR::d]) const override;
/// Set particle density on the cell.
void defineRho(Cell<T,DESCRIPTOR>& cell, T rho) override;
/// Set fluid velocity on the cell.
void defineU(Cell<T,DESCRIPTOR>& cell, const T u[DESCRIPTOR::d]) override;
private:
T omega;
};
}
#endif
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