forcedpoiseuille.cpp

open lattice boltzmann project www.openlb.org

/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2007 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.
*/

#include "olb2D.h"
#include "olb2D.hh"   // use only generic version
#include <vector>
#include <cmath>
#include <iostream>
#include <iomanip>
#include <fstream>

using namespace olb;
using namespace olb::descriptors;
using namespace olb::graphics;
using namespace std;

typedef double T;
#define DESCRIPTOR ForcedD2Q9Descriptor

T poiseuilleVelocity(int iY, LBunits<T> const& converter) {
    T y = (T)iY / converter.getResolution();
    return 4.*converter.getLatticeU() * (y-y*y);
}

T poiseuillePressure(int iX, LBunits<T> const& converter) {
    T Lx = converter.getNx()-1;
    T Ly = converter.getNy()-1;
    return 8.*converter.getLatticeNu()*converter.getLatticeU() /
           (Ly*Ly) * (Lx/(T)2-(T)iX);
}

T poiseuilleForce(LBunits<T> const& converter) {
    T Ly = converter.getNy()-1;
    return 8.*converter.getLatticeNu()*converter.getLatticeU() / (Ly*Ly);
}

void iniGeometry( BlockStructure2D<T, DESCRIPTOR>& lattice,
                  LBunits<T> const& converter,
                  Dynamics<T, DESCRIPTOR>& bulkDynamics,
                  OnLatticeBoundaryCondition2D<T,DESCRIPTOR>& boundaryCondition )
{
    int nx = converter.getNx();
    int ny = converter.getNy();
    T   omega = converter.getOmega();
    lattice.defineDynamics(0,nx-1, 0,ny-1, &bulkDynamics);

    boundaryCondition.addVelocityBoundary1P(1,nx-2,ny-1,ny-1, omega);
    boundaryCondition.addVelocityBoundary1N(1,nx-2,   0,   0, omega);

    boundaryCondition.addExternalVelocityCornerNN(0,0, omega);
    boundaryCondition.addExternalVelocityCornerNP(0,ny-1, omega);
    boundaryCondition.addExternalVelocityCornerPN(nx-1,0, omega);
    boundaryCondition.addExternalVelocityCornerPP(nx-1,ny-1, omega);

    for (int iX=0; iX<nx; ++iX) {
        for (int iY=0; iY<ny; ++iY) {
            T force[2] = { poiseuilleForce(converter), T() };
            lattice.get(iX,iY).defineExternalField (
                           DESCRIPTOR<T>::ExternalField::forceBeginsAt,
                           DESCRIPTOR<T>::ExternalField::sizeOfForce,
                           force
            );
        }
    }

    lattice.initialize();
}

void plotStatistics(int                              iT,
                    BlockStructure2D<T, DESCRIPTOR>& lattice,
                    LBunits<T>&                      converter,
                    T                                middleU)
{
    T dx = converter.getDeltaX();
    T dt = converter.getDeltaT();
    cout << "Iteration " << setw(5) << iT;
    cout << "; t=" << setprecision(3) << setw(6)
         << iT*converter.getDeltaT();
    cout << "; E=" << setprecision(10) << setw(15)
         << lattice.getStatistics().getAverageEnergy()*dx*dx/dt/dt;
    cout << "; rho=" << setprecision(8) << setw(11)
         << lattice.getStatistics().getAverageRho();
    cout << "; uMax= " << setprecision(8) << setw(11)
         << middleU*dx/dt;
    cout << endl;
}

void produceGif(int iT, BlockStructure2D<T, DESCRIPTOR>& lattice) {
    const int imSize = 400;
    DataAnalysisBase2D<T,DESCRIPTOR> const& analysis = lattice.getDataAnalysis();

    ImageWriter<T> imageWriter("leeloo");
    imageWriter.writeScaledGif(createFileName("p", iT, 6),
                               analysis.getPressure(), imSize, imSize);
    imageWriter.writeScaledGif(createFileName("u", iT, 6),
                               analysis.getVelocityNorm(), imSize, imSize);
}

void writeProfile ( string fName,
                    BlockStructure2D<T, DESCRIPTOR>& lattice,
                    LBunits<T>& converter )
{
    ofstream *ofile = 0;
    if (singleton::mpi().isMainProcessor()) {
        ofile = new ofstream((singleton::directories().getLogOutDir()+fName).c_str());
    }
    for (int iY=0; iY<converter.getNy(); ++iY) {
        T dx = converter.getDeltaX();
        T dt = converter.getDeltaT();
        T analytical = poiseuilleVelocity(iY, converter);
        T numerical[2];
        lattice.get(converter.getNx()/2, iY).computeU(numerical);

        if (singleton::mpi().isMainProcessor()) {
            *ofile << iY*dx << " " << analytical*dx/dt
                            << " " << numerical[0]*dx/dt << "\n";
        }
    }
    delete ofile;
}


int main(int argc, char* argv[]) {
    olbInit(&argc, &argv);
    singleton::directories().setOutputDir("./tmp/");

    const T uMax = 0.02;
    const T Re   = 10.;
    const int N  = 50;

    const T lx   = 2.;
    const T ly   = 1.;

    const int maxIter  = 20000;
    const int saveIter = 2000;
    const int statIter = 200;

    LBunits<T> converter(uMax, Re, N, lx, ly);
    writeLogFile(converter, "2D Poiseuille flow");

#ifndef PARALLEL_MODE_MPI  // sequential program execution
    BlockLattice2D<T, DESCRIPTOR> lattice(converter.getNx(), converter.getNy() );
#else                      // parallel program execution
    MultiBlockLattice2D<T, DESCRIPTOR> lattice (
        createRegularDataDistribution( converter.getNx(), converter.getNy() ) );
#endif


    // choose between local and non-local boundary condition
    OnLatticeBoundaryCondition2D<T,DESCRIPTOR>*
        boundaryCondition = createInterpBoundaryCondition2D(lattice);
        // boundaryCondition = createLocalBoundaryCondition2D(lattice);

    ForcedBGKdynamics<T, DESCRIPTOR> bulkDynamics (
                      converter.getOmega(),
                      instances::getBulkMomenta<T,DESCRIPTOR>()
    );

    iniGeometry(lattice, converter, bulkDynamics, *boundaryCondition);

    for (int iT=0; iT<maxIter; ++iT) {
        if (iT%statIter==0) {
            T middleU[2];
            lattice.get(converter.getNx()/2, converter.getNy()/2).computeU(middleU);
            plotStatistics(iT, lattice, converter, middleU[0]);
        }

        if (iT%saveIter==0) {
            produceGif(iT, lattice);
            writeProfile("centerVel.dat", lattice, converter);
        }

        lattice.collideAndStream(true);
    }

    delete boundaryCondition;
}