[achodankar]

The code snippet is called in the main function while timestepping:

for (std::size_t iT = 0; iT < converter.getLatticeTime(maxPhysT)+10; ++iT) {
particle.simulateTimestep(“verlet”);
getResults(sLattice, converter, iT, superGeometry, timer, circle1, circle2);
sLattice.collideAndStream();
superExt1.communicate();
superExt2.communicate();
superExt3.communicate();

}

[achodankar]

I am running the dkt2d example. The simulation results are correct when I view it in Paraview and usin ppm images. here is the code snippet:

void getResults(SuperLattice2D<T, DESCRIPTOR>& sLattice,
UnitConverter<T,DESCRIPTOR> const& converter, int iT,
SuperGeometry2D<T>& superGeometry, Timer<double>& timer, SmoothIndicatorF2D<T,T,true> &particle1, SmoothIndicatorF2D<T,T,true> &particle2)
{
OstreamManager clout(std::cout, “getResults”);

#ifdef WriteVTK
SuperVTMwriter2D<T> vtkWriter(“sedimentation”);
SuperLatticePhysVelocity2D<T, DESCRIPTOR> velocity(sLattice, converter);
SuperLatticePhysPressure2D<T, DESCRIPTOR> pressure(sLattice, converter);
SuperLatticePhysExternalPorosity2D<T, DESCRIPTOR> externalPor(sLattice, converter);
vtkWriter.addFunctor(velocity);
vtkWriter.addFunctor(pressure);
vtkWriter.addFunctor(externalPor);

if (iT == 0) {
converter.write(“dkt”);
SuperLatticeGeometry2D<T, DESCRIPTOR> geometry(sLattice, superGeometry);
SuperLatticeCuboid2D<T, DESCRIPTOR> cuboid(sLattice);
SuperLatticeRank2D<T, DESCRIPTOR> rank(sLattice);
vtkWriter.write(geometry);
vtkWriter.write(cuboid);
vtkWriter.write(rank);
vtkWriter.createMasterFile();

}

if (iT % converter.getLatticeTime(iTwrite) == 0) {
vtkWriter.write(iT);
}

// Writes the vtk files
const int vtkIter = converter.getLatticeTime( .3 );
if ( iT%vtkIter == 0 && iT > 0 ) {
vtkWriter.write( iT );

{
SuperEuklidNorm2D<T, DESCRIPTOR> normVel( velocity );
BlockReduction2D2D<T> planeReduction( normVel, 600, BlockDataSyncMode::ReduceOnly );
// write output as JPEG
heatmap::write(planeReduction, iT);

}

//plot a gif of the simulation
{
SuperEuklidNorm2D<T,DESCRIPTOR> normVel( velocity );
BlockReduction2D2D<T> planeReduction( normVel );
//BlockReduction2D2D<T> planeReduction(normVel, sLattice);
BlockGifWriter<T> gifWriter;
//gifWriter.write(planeReduction, 0, 0.7, iT, “vel”); //static scale
gifWriter.write( planeReduction, iT, ” vel ” ); // scaled
//SuperEuklidNorm2D<T,DESCRIPTOR> press( pressure );
//BlockReduction2D2D<T> planeReduction( press );
//gifWriter.write( planeReduction, iT, ” press ” ); // scaled
}
{

BlockGifWriter<T> gifWriter;
SuperEuklidNorm2D<T,DESCRIPTOR> press( pressure );
BlockReduction2D2D<T> planeReduction( press );
gifWriter.write( planeReduction, iT, ” press ” ); // scaled
}

{
SuperLatticePhysVelocity2D<T,DESCRIPTOR> velocityF(sLattice, converter);
BlockReduction2D2D<T> velocityPlane(velocityF, 600, BlockDataSyncMode::ReduceOnly);
ofstream myfile1;
myfile1.open(“velocity_”+ std::to_string(iT) + “.csv”);
myfile1 << “i,” << “j,” << “Ux,” <<“Uy”<< std::endl;
int latticeR[2] { };
T vel[2] { };
velocityPlane(vel, latticeR);
for (latticeR[0]=0; latticeR[0] < velocityPlane.getBlockStructure().getNx(); ++latticeR[0])
{
for (latticeR[1]=0; latticeR[1] < velocityPlane.getBlockStructure().getNy(); ++latticeR[1])
{
//cout<<“Enter-“<<std::endl;
myfile1 << latticeR[0] << “,” << latticeR[1] << “,”<< vel[0] << “,”<< vel[1] << std::endl;
}
}
myfile1.close();

}

}
#endif

#ifdef WriteGnuPlot
if (iT % converter.getLatticeTime(iTwrite) == 0) {
if (singleton::mpi().getRank() == 0) {

ofstream myfile;
myfile.open (gnuplotFilename.c_str(), ios::app);
myfile
<< converter.getPhysTime(iT) << ” ”
<< std::setprecision(9)
<< particle2.getPos()[1] << ” ”
<< particle1.getPos()[1] << ” ”
<< particle2.getPos()[0] << ” ”
<< particle1.getPos()[0] << endl;
myfile.close();
}
}
#endif

/// Writes output on the console
if (iT % converter.getLatticeTime(iTwrite) == 0) {
timer.update(iT);
timer.printStep();
sLattice.getStatistics().print(iT, converter.getPhysTime(iT));
}

return;
}

[achodankar]

Hello Adrian,
Thank you. This fixes the problem. I missed on that bug. The velocity values are showing up to be zero for all time steps in the csv files. Is the above way the right way to extract the velocity values?

Thank you.

Yours sincerely,

Abhijeet

[achodankar]

Hello Nicolas,
Thank you for your prompt response.

Yours sincerely,

Abhijeet

[achodankar]

Hello Developers,
I was able to set the periodic boundary conditions using
cuboidGeometry.setPeriodicity(true,false ); in the dkt2d example in the x direction. However, the particles gets absorbed in the exit and won’t re-enter the simulation from the inlet. Am I doing anything wrong in the implementation process?

Thank you.

Yours sincerely,

Abhijeet

[achodankar]

Hello Adrian,
Thank you very much for your prompt reply. The proposed solution fixed the issue.

Thank you.

Yours sincerely,

Abhijeet

[achodankar]

Hello,
I was able to run the .p scripts using gnuplot-x11 and get the corresponding images and pdfs. However, I had to do all of it manually. How should I modify OpenLB code to use gnuplot-x11? I have uninstalled the gnuplot version, so I just have the gnuplot-x11 version presently.

[Author]

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