zouhedynamics.hh

open lattice boltzmann project www.openlb.org

/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2006,2007 Orestis Malaspinas and Jonas Latt
 *  Address: Rue General Dufour 24,  1211 Geneva 4, Switzerland 
 *  E-mail: [e-mail]
 *
 *  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 ZOU_HE_DYNAMICS_HH
#define ZOU_HE_DYNAMICS_HH

#include "zouHeDynamics.h"
#include "core/latticeDescriptors.h"
#include "core/util.h"
#include "core/lbHelpers.h"
#include <cmath>


namespace olb {

using namespace descriptors;

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::ZouHeDynamics (
        T omega_, Momenta<T,Lattice>& momenta_ )
    : BasicDynamics<T,Lattice>(momenta_),
      boundaryDynamics(omega_, momenta_)
{ }

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>*
    ZouHeDynamics<T,Lattice, Dynamics, direction, orientation>::clone() const
{
    return new ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>(*this);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
T ZouHeDynamics<T,Lattice, Dynamics, direction, orientation>::
    computeEquilibrium(int iPop, T rho, const T u[Lattice<T>::d], T uSqr) const
{
    return boundaryDynamics.computeEquilibrium(iPop, rho, u, uSqr);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
void ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::collide (
        Cell<T,Lattice>& cell,
        LatticeStatistics<T>& statistics )
{
    typedef lbHelpers<T,Lattice> lbH;
    typedef Lattice<T> L;

    // Along all the commented parts of this code there will be an example based
    // on the situation where the wall's normal vector if (0,1) and the
    // numerotation of the velocites are done according to the D2Q9 
    // lattice of the OpenLB library.

    // Find all the missing populations
    // (directions 3,4,5)
    std::vector<int> missingIndexes = util::subIndexOutgoing<L,direction,orientation>();
    
    // Will contain the missing poputations that are not normal to the wall.
    // (directions 3,5)
    std::vector<int> missingDiagonalIndexes = missingIndexes;
    for (unsigned iPop = 0; iPop < missingIndexes.size(); ++iPop)
    {
        int numOfNonNullComp = 0;
        for (int iDim = 0; iDim < L:: d; ++iDim)
            numOfNonNullComp += abs(L::c[missingIndexes[iPop]][iDim]);

        if (numOfNonNullComp == 1)
        {
            missingDiagonalIndexes.erase(missingDiagonalIndexes.begin()+iPop);
            break;
        }
    }

    T rho, u[L::d];
    T falseRho, falseU[L::d];
    this->momenta.computeRhoU(cell, rho, u);

    T uSqr = util::normSqr<T,L::d>(u);

    // The unknown non equilibrium populations are bounced back
    // (f[3] = feq[3] + fneq[7], f[4] = feq[4] + fneq[8], 
    //  f[5] = feq[5] + fneq[1])
    for (unsigned iPop = 0; iPop < missingIndexes.size(); ++iPop)
    {
        cell[missingIndexes[iPop]] = cell[util::opposite<L>(missingIndexes[iPop])]
            - computeEquilibrium(util::opposite<L>(missingIndexes[iPop]), rho, u, uSqr)
            + computeEquilibrium(missingIndexes[iPop], rho, u, uSqr);
    }

    // We recompute rho and u in order to have the new momentum and density. Since
    // the momentum is not conserved from this scheme, we will corect it. By adding
    // a contribution to the missingDiagonalVelocities.
    lbH::computeRhoU(cell,falseRho,falseU);

    T diff[L::d];
    for (int iDim = 0; iDim < L:: d; ++iDim)
        diff[iDim] = (rho*u[iDim] - falseRho*falseU[iDim])/ (T)missingDiagonalIndexes.size();

    for (unsigned iPop = 0; iPop < missingDiagonalIndexes.size(); ++iPop)
    {
        for (int iDim = 1; iDim < L::d; ++iDim)
        {
            cell[missingDiagonalIndexes[iPop]] +=
                    L::c[missingDiagonalIndexes[iPop]][(direction+iDim)%L::d] * diff[(direction+iDim)%L::d];
        }
    }

    boundaryDynamics.collide(cell, statistics);

    statistics.gatherStats(rho, uSqr);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
void ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::staticCollide (
        Cell<T,Lattice>& cell,
        const T u[Lattice<T>::d],
        LatticeStatistics<T>& statistics )
{
    typedef lbHelpers<T,Lattice> lbH;
    typedef Lattice<T> L;

    std::vector<int> missingIndexes = util::subIndexOutgoing<L,direction,orientation>();
    std::vector<int> missingDiagonalIndexes = missingIndexes;

    for (unsigned iPop = 0; iPop < missingIndexes.size(); ++iPop)
    {
        int numOfNonNullComp = 0;
        for (int iDim = 0; iDim < L:: d; ++iDim)
            numOfNonNullComp += abs(L::c[missingIndexes[iPop]][iDim]);

        if (numOfNonNullComp == 1)
        {
            missingDiagonalIndexes.erase(missingDiagonalIndexes.begin()+iPop);
            break;
        }
    }

    T rho = this->momenta.computeRho(cell);

    T uSqr = util::normSqr<T,L::d>(u);

    for (unsigned iPop = 0; iPop < missingIndexes.size(); ++iPop)
    {
        cell[missingIndexes[iPop]] = cell[util::opposite<L>(missingIndexes[iPop])]
            - computeEquilibrium(util::opposite<L>(missingIndexes[iPop]), rho, u, uSqr)
            + computeEquilibrium(missingIndexes[iPop], rho, u, uSqr);
    }

    T falseRho, falseU[L::d];
    lbH::computeRhoU(cell,falseRho,falseU);

    T diff[L::d];
    for (int iDim = 0; iDim < L:: d; ++iDim)
        diff[iDim] = (rho*u[iDim] - falseRho*falseU[iDim])/ (T)missingDiagonalIndexes.size();

    for (unsigned iPop = 0; iPop < missingDiagonalIndexes.size(); ++iPop)
    {
        for (int iDim = 1; iDim < L::d; ++iDim)
        {
            cell[missingDiagonalIndexes[iPop]] +=
                    L::c[missingDiagonalIndexes[iPop]][(direction+iDim)%L::d] * diff[(direction+iDim)%L::d];
        }
    }

    boundaryDynamics.staticCollide(cell, u, statistics);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
T ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::getOmega() const 
{
    return boundaryDynamics.getOmega();
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
void ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::setOmega(T omega_)
{
    boundaryDynamics.setOmega(omega_);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
T ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::getParameter(int whichParameter) const 
{
    return boundaryDynamics.getParameter(whichParameter);
}

template<typename T, template<typename U> class Lattice, typename Dynamics, int direction, int orientation>
void ZouHeDynamics<T,Lattice,Dynamics,direction,orientation>::setParameter(int whichParameter, T value)
{
    boundaryDynamics.setParameter(whichParameter, value);
}


}  // namespace olb

#endif