畢業了——課題代碼開源（二）使用Palabos的單相流多孔滲流代碼

簡介

這是我依據Palabos案例解析（一）permeability.cpp案例的原始案例修改的適合我自己的代碼，其實沒咋動，主要就是改一下最後速度的統計的標準和數據輸出的一些小東西，其實和源代碼幾乎沒啥區別。

代碼

#include "palabos3D.h"
#include "palabos3D.hh"

#include <vector>
#include <cmath>
#include <cstdlib>

using namespace plb;

typedef double T;
#define DESCRIPTOR descriptors::D3Q19Descriptor

// This function object returns a zero velocity, and a pressure which decreases
//   linearly in z-direction. It is used to initialize the particle populations.
class PressureGradient {
public:
    PressureGradient(T deltaP_, plint nx_) : deltaP(deltaP_), nx(nx_)
    { }
    void operator() (plint iX, plint iY, plint iZ, T& density, Array<T,3>& velocity) const
    {
        velocity.resetToZero();
        density = (T)1 - deltaP*DESCRIPTOR<T>::invCs2 / (T)(nx-1) * (T)iX;
    }
private:
    T deltaP;
    plint nx;
};

void readGeometry(std::string fNameIn, std::string fNameOut, MultiScalarField3D<int>& geometry)
{
    const plint nx = geometry.getNx();
    const plint ny = geometry.getNy();
    const plint nz = geometry.getNz();

    Box3D sliceBox(0,0, 0,ny-1, 0,nz-1);
    std::auto_ptr<MultiScalarField3D<int> > slice = generateMultiScalarField<int>(geometry, sliceBox);
    plb_ifstream geometryFile(fNameIn.c_str());
    for (plint iX=0; iX<nx; ++iX) {
        if (!geometryFile.is_open()) {
            pcout << "Error: could not open geometry file " << fNameIn << std::endl;
            exit(EXIT_FAILURE);
        }
        geometryFile >> *slice;
        copy(*slice, slice->getBoundingBox(), geometry, Box3D(iX,iX, 0,ny-1, 0,nz-1));
    }

    {
        VtkImageOutput3D<T> vtkOut("porousMedium", 1.0);
        vtkOut.writeData<float>(*copyConvert<int,T>(geometry, geometry.getBoundingBox()), "tag", 1.0);
    }

    {
        /*std::auto_ptr<MultiScalarField3D<T> > floatTags = copyConvert<int,T>(geometry, geometry.getBoundingBox());
        std::vector<T> isoLevels;
        isoLevels.push_back(0.5);
        typedef TriangleSet<T>::Triangle Triangle;
        std::vector<Triangle> triangles;
        Box3D domain = floatTags->getBoundingBox().enlarge(-1);
        domain.x0++;
        domain.x1--;
        isoSurfaceMarchingCube(triangles, *floatTags, isoLevels, domain);
        TriangleSet<T> set(triangles);
        std::string outDir = fNameOut + "/";
        set.writeBinarySTL(outDir + "porousMedium.stl");*/
    }
}

void porousMediaSetup(MultiBlockLattice3D<T,DESCRIPTOR>& lattice,
        OnLatticeBoundaryCondition3D<T,DESCRIPTOR>* boundaryCondition,
        MultiScalarField3D<int>& geometry, T deltaP)
{
    const plint nx = lattice.getNx();
    const plint ny = lattice.getNy();
    const plint nz = lattice.getNz();

    pcout << "Definition of inlet/outlet." << std::endl;
    Box3D inlet (1,nx-2, 1,ny-2, 0,0);
    boundaryCondition->addPressureBoundary0N(inlet, lattice);
    setBoundaryDensity(lattice, inlet, (T) 1.);

    Box3D outlet(1,nx-2, 1,ny-2, nz-1,nz-1);
    boundaryCondition->addPressureBoundary0P(outlet, lattice);
    setBoundaryDensity(lattice, outlet, (T) 1. - deltaP*DESCRIPTOR<T>::invCs2);

    pcout << "Definition of the geometry." << std::endl;
    // Where "geometry" evaluates to 1, use bounce-back.
    defineDynamics(lattice, geometry, new BounceBack<T,DESCRIPTOR>(), 1);
    // Where "geometry" evaluates to 2, use no-dynamics (which does nothing).
    defineDynamics(lattice, geometry, new NoDynamics<T,DESCRIPTOR>(), 2);

    Box3D X0Plane(0,0,0,ny-1,0,nz-1);
    Box3D XnPlane(nx-1,nx-1,0,ny-1,0,nz-1);
    Box3D Y0Plane(0,nx-1,0,0,0,nz-1);
    Box3D YnPlane(0,nx-1,ny-1,ny-1,0,nz-1);
    defineDynamics(lattice, X0Plane, new BounceBack<T,DESCRIPTOR>());
    defineDynamics(lattice, XnPlane, new BounceBack<T,DESCRIPTOR>());
    defineDynamics(lattice, Y0Plane, new BounceBack<T,DESCRIPTOR>());
    defineDynamics(lattice, YnPlane, new BounceBack<T,DESCRIPTOR>());

    pcout << "Initilization of rho and u." << std::endl;
    initializeAtEquilibrium( lattice, lattice.getBoundingBox(), PressureGradient(deltaP, nx) );

    lattice.initialize();
    delete boundaryCondition;
}

void writeGifs(MultiBlockLattice3D<T,DESCRIPTOR>& lattice, plint iter)
{
    const plint nx = lattice.getNx();
    const plint ny = lattice.getNy();
    const plint nz = lattice.getNz();

    const plint imSize = 600;
    ImageWriter<T> imageWriter("leeloo");

    // Write velocity-norm at x=0.
    imageWriter.writeScaledGif(createFileName("ux_inlet", iter, 6),
            *computeVelocityNorm(lattice, Box3D(0,0, 0,ny-1, 0,nz-1)),
            imSize, imSize );

    // Write velocity-norm at x=nx/2.
    imageWriter.writeScaledGif(createFileName("ux_half", iter, 6),
            *computeVelocityNorm(lattice, Box3D(nx/2,nx/2, 0,ny-1, 0,nz-1)),
            imSize, imSize );
}

void writeVTK(MultiBlockLattice3D<T,DESCRIPTOR>& lattice, plint iter)
{
    VtkImageOutput3D<T> vtkOut(createFileName("vtk", iter, 6), 1.);
    vtkOut.writeData<float>(*computeVelocityNorm(lattice), "velocityNorm", 1.);
    vtkOut.writeData<3,float>(*computeVelocity(lattice), "velocity", 1.);
}

T computePermeability(MultiBlockLattice3D<T,DESCRIPTOR>& lattice, T nu, T deltaP, Box3D domain )
{
    pcout << "Computing the permeability." << std::endl;

    // Compute only the z-direction of the velocity (direction of the flow).
    plint zComponent = 2;
    plint nz = lattice.getNz();

    T meanU = computeAverage(*computeVelocityComponent(lattice, domain, zComponent));

    pcout << "Average velocity     = " << meanU                         << std::endl;
    pcout << "Lattice viscosity nu = " << nu                            << std::endl;
    pcout << "Grad P               = " << deltaP/(T)(nz-1)              << std::endl;
    pcout << "Permeability         = " << nu*meanU / (deltaP/(T)(nz-1)) << std::endl;

    return meanU;
}

int main(int argc, char **argv)
{
    plbInit(&argc, &argv);

    if (argc!=7) {
        pcout << "Error missing some input parameter\n";
        pcout << "The structure is :\n";
        pcout << "1. Input file name.\n";
        pcout << "2. Output directory name.\n";
        pcout << "3. number of cells in X direction.\n";
        pcout << "4. number of cells in Y direction.\n";
        pcout << "5. number of cells in Z direction.\n";
        pcout << "6. Delta P .\n";
        pcout << "Example: " << argv[0] << " palabos.dat tmp/ 201 201 201 0.00005\n";
        exit (EXIT_FAILURE);
    }
    std::string fNameIn  = argv[1];
    std::string fNameOut = argv[2];

    const plint nx = atoi(argv[3]);
    const plint ny = atoi(argv[4]);
    const plint nz = atoi(argv[5]);
    const T deltaP = atof(argv[6]);

    global::directories().setOutputDir(fNameOut+"/");

    const T omega = 1.0;
    const T nu    = ((T)1/omega- (T)0.5)/DESCRIPTOR<T>::invCs2;

    pcout << "Creation of the lattice." << std::endl;
    MultiBlockLattice3D<T,DESCRIPTOR> lattice(nx,ny,nz, new BGKdynamics<T,DESCRIPTOR>(omega));
    // Switch off periodicity.
    lattice.periodicity().toggleAll(false);

    pcout << "Reading the geometry file." << std::endl;
    MultiScalarField3D<int> geometry(nx,ny,nz);
    readGeometry(fNameIn, fNameOut, geometry);

    pcout << "nu = " << nu << std::endl;
    pcout << "deltaP = " << deltaP << std::endl;
    pcout << "omega = " << omega << std::endl;
    pcout << "nx = " << lattice.getNx() << std::endl;
    pcout << "ny = " << lattice.getNy() << std::endl;
    pcout << "nz = " << lattice.getNz() << std::endl;

    porousMediaSetup(lattice, createLocalBoundaryCondition3D<T,DESCRIPTOR>(), geometry, deltaP);

    Box3D Z0Plane(1,nx-2,1,ny-2,0,50);
    Box3D ZnPlane(1,nx-2,1,ny-2,nz-50,nz-1);

    defineDynamics(lattice, Z0Plane, new BGKdynamics<T,DESCRIPTOR>(omega));
    defineDynamics(lattice, ZnPlane, new BGKdynamics<T,DESCRIPTOR>(omega));

    // The value-tracer is used to stop the simulation once is has converged.
    // 1st parameter:velocity
    // 2nd parameter:size
    // 3rd parameters:threshold
    // 1st and second parameters ae used for the length of the time average (size/velocity)
    util::ValueTracer<T> converge(1.0,1000.0,1.0e-4);

    pcout << "Simulation begins" << std::endl;
    plint iT=0;

    const plint maxT = 30000;
    for (;iT<maxT; ++iT) {
        if (iT % 20 == 0) {
            pcout << "Iteration " << iT << std::endl;
        }
        /*if (iT % 500 == 0 && iT>0) {
            writeGifs(lattice,iT);
        }*/

        lattice.collideAndStream();
        converge.takeValue(getStoredAverageEnergy(lattice),true);

        if (converge.hasConverged()) {
            break;
        }
    }

    pcout << "End of simulation at iteration " << iT << std::endl;

    pcout << "Permeability:" << std::endl << std::endl;
    computePermeability(lattice, nu, deltaP, lattice.getBoundingBox());
    pcout << std::endl;

    pcout << "Writing VTK file ..." << std::endl << std::endl;
    writeVTK(lattice,iT);
    pcout << "Finished!" << std::endl << std::endl;

    return 0;
}

說明

其實這個是沒啥可說的，對於參數，我並沒有特別的調過，還需要你自己依照自己課題的對應尺寸去調，圖片就不放了，跟那個滲透的案例差不多，想看圖的可以看那個的圖。

附加題

代碼

#include "palabos2D.h"
#include "palabos2D.hh"

#include <vector>
#include <cmath>
#include <cstdlib>

using namespace plb;

typedef double T;
#define DESCRIPTOR descriptors::D2Q9Descriptor

// This function object returns a zero velocity, and a pressure which decreases
//   linearly in z-direction. It is used to initialize the particle populations.
class PressureGradient {
public:
    PressureGradient(T deltaP_, plint ny_) : deltaP(deltaP_), ny(ny_)
    { }
    void operator() (plint iX, plint iY, T& density, Array<T,2>& velocity) const
    {
        velocity.resetToZero();
        density = (T)1 - deltaP*DESCRIPTOR<T>::invCs2 / (T)(ny-1) * (T)(ny-1-iY);
    }
private:
    T deltaP;
    plint ny;
};

void readGeometry(std::string fNameIn, std::string fNameOut, MultiScalarField2D<int>& geometry)
{
    plb_ifstream geometryFile(fNameIn.c_str());
    if (!geometryFile.is_open()) {
        pcout << "Error: could not open geometry file " << fNameIn << std::endl;
        exit(EXIT_FAILURE);
    }
    geometryFile >> geometry;

    {
        VtkImageOutput2D<T> vtkOut("porousMedium", 1.0);
        vtkOut.writeData<float>(*copyConvert<int,T>(geometry, geometry.getBoundingBox()), "tag", 1.0);
    }
}

void porousMediaSetup(MultiBlockLattice2D<T,DESCRIPTOR>& lattice,
        OnLatticeBoundaryCondition2D<T,DESCRIPTOR>* boundaryCondition,
        MultiScalarField2D<int>& geometry, T deltaP)
{
    const plint nx = lattice.getNx();
    const plint ny = lattice.getNy();

    pcout << "Definition of inlet/outlet." << std::endl;
    Box2D inlet (1,nx-2, ny-1,ny-1);
    boundaryCondition->addPressureBoundary1P(inlet, lattice);
    setBoundaryDensity(lattice, inlet, (T) 1.);

    Box2D outlet(1,nx-2, 0,0);
    boundaryCondition->addPressureBoundary1N(outlet, lattice);
    setBoundaryDensity(lattice, outlet, (T) 1. - deltaP*DESCRIPTOR<T>::invCs2);

    pcout << "Definition of the geometry." << std::endl;
    // Where "geometry" evaluates to 1, use bounce-back.
    defineDynamics(lattice, geometry, new BounceBack<T,DESCRIPTOR>(), 1);
    // Where "geometry" evaluates to 2, use no-dynamics (which does nothing).
    defineDynamics(lattice, geometry, new NoDynamics<T,DESCRIPTOR>(), 2);

    pcout << "Initilization of rho and u." << std::endl;
    initializeAtEquilibrium( lattice, lattice.getBoundingBox(), PressureGradient(deltaP, ny) );

    lattice.initialize();
    delete boundaryCondition;
}

void writeGifs(MultiBlockLattice2D<T,DESCRIPTOR>& lattice, plint iter)
{
    const plint nx = lattice.getNx();
    const plint ny = lattice.getNy();

    const plint imSize = 600;
    ImageWriter<T> imageWriter("leeloo");

    imageWriter.writeScaledGif(createFileName("u", iter, 6),
            *computeVelocityNorm(lattice, Box2D(0,nx-1, 0,ny-1)),
            imSize, imSize );
}

void writeVTK(MultiBlockLattice2D<T,DESCRIPTOR>& lattice, plint iter)
{
    VtkImageOutput2D<T> vtkOut(createFileName("vtk", iter, 6), 1.);
    vtkOut.writeData<float>(*computeVelocityNorm(lattice), "velocityNorm", 1.);
    vtkOut.writeData<2,float>(*computeVelocity(lattice), "velocity", 1.);
}

T computePermeability(MultiBlockLattice2D<T,DESCRIPTOR>& lattice, T nu, T deltaP, Box2D domain )
{
    pcout << "Computing the permeability." << std::endl;

    // Compute only the y-direction of the velocity (direction of the flow).
    plint yComponent = 1;
    plint ny = lattice.getNy();

    T meanU = -computeAverage(*computeVelocityComponent(lattice, domain, yComponent));

    pcout << "Average velocity     = " << meanU                         << std::endl;
    pcout << "Lattice viscosity nu = " << nu                            << std::endl;
    pcout << "Grad P               = " << deltaP/(T)(ny-1)              << std::endl;
    pcout << "Permeability         = " << nu*meanU / (deltaP/(T)(ny-1)) << std::endl;

    return meanU;
}

int main(int argc, char **argv)
{
    plbInit(&argc, &argv);

    if (argc!=6) {
        pcout << "Error missing some input parameter\n";
        pcout << "The structure is :\n";
        pcout << "1. Input file name.\n";
        pcout << "2. Output directory name.\n";
        pcout << "3. number of cells in X direction.\n";
        pcout << "4. number of cells in Y direction.\n";
        pcout << "5. Delta P .\n";
        pcout << "Example: " << argv[0] << " palabos.dat tmp/ 201 201 0.00005\n";
        exit (EXIT_FAILURE);
    }
    std::string fNameIn  = argv[1];
    std::string fNameOut = argv[2];

    const plint nx = atoi(argv[3]);
    const plint ny = atoi(argv[4]);
    const T deltaP = atof(argv[5]);

    global::directories().setOutputDir(fNameOut+"/");

    const T omega = 1.0;
    const T nu    = ((T)1/omega- (T)0.5)/DESCRIPTOR<T>::invCs2;

    pcout << "Creation of the lattice." << std::endl;
    MultiBlockLattice2D<T,DESCRIPTOR> lattice(nx,ny, new BGKdynamics<T,DESCRIPTOR>(omega));
    // Switch off periodicity.
    lattice.periodicity().toggleAll(false);

    pcout << "Reading the geometry file." << std::endl;
    MultiScalarField2D<int> geometry(nx,ny);
    readGeometry(fNameIn, fNameOut, geometry);

    pcout << "nu = " << nu << std::endl;
    pcout << "deltaP = " << deltaP << std::endl;
    pcout << "omega = " << omega << std::endl;
    pcout << "nx = " << lattice.getNx() << std::endl;
    pcout << "ny = " << lattice.getNy() << std::endl;

    porousMediaSetup(lattice, createLocalBoundaryCondition2D<T,DESCRIPTOR>(), geometry, deltaP);

    // The value-tracer is used to stop the simulation once is has converged.
    // 1st parameter:velocity
    // 2nd parameter:size
    // 3rd parameters:threshold
    // 1st and second parameters ae used for the length of the time average (size/velocity)
    util::ValueTracer<T> converge(1.0,1000.0,1.0e-4);

    pcout << "Simulation begins" << std::endl;
    plint iT=0;

    const plint maxT = 100000;
    for (;iT<maxT; ++iT) {
        if (iT % 20 == 0) {
            pcout << "Iteration " << iT << std::endl;
        }
        if (iT % 50 == 0 && iT>0) {
            writeGifs(lattice,iT);
        }

        lattice.collideAndStream();
        converge.takeValue(getStoredAverageEnergy(lattice),true);

        if (converge.hasConverged()) {
            break;
        }
    }

    pcout << "End of simulation at iteration " << iT << std::endl;

    pcout << "Permeability:" << std::endl << std::endl;
    computePermeability(lattice, nu, deltaP, lattice.getBoundingBox());
    pcout << std::endl;

    pcout << "Writing VTK file ..." << std::endl << std::endl;
    writeVTK(lattice,iT);
    pcout << "Finished!" << std::endl << std::endl;

    return 0;
}

說明

這是二維的滲透，僅僅是拿三維直接改的版本，對於參數，我也是並沒有特別的細究，對於此程序，可以和上面三維的和原始滲透案例進行一下對比，你就明白在palabos中如何三維轉二維和二維轉三維。

完