[Junming Duan]

Dear all,

I'm doing a simulation of flow past a rotating 2D cylinder with OpenFOAM-v2006.
The center of the cylinder is at (0,0), and the whole domain is (-0.6, 0.8) \times (-0.6, 0.6).
I want to extract the cell center pressure in a small part around the cylinder by using topoSet and sampling.
Here is the code

 /*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     pimpleFoam;

......

functions
{
  Sampling_rec
  {
    type surfaces;
    libs ("libsampling.so");
    interpolationScheme cellPointFace;
    surfaceFormat raw;
    fields (p);

    surfaces
    {
      rec
      {
        type            plane;
        zone            rec_extract;
        planeType       pointAndNormal;
        pointAndNormalDict
        {
          point       (0 0 -0.24725);
          normal      (0 0 1);
        }
        interpolate     true;
        triangulate     false;
      }
    }

    timeStart       0;
    timeEnd         10;
    executeControl  writeTime;
    executeInterval 1;
    writeControl    writeTime;
    writeInterval   1;
  }

}
// ************************************************************************* //

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      topoSetDict;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

actions
(

    {
        name    rec_extract;
        type    cellSet;
        action  new;
        source  boxToCell;
        box     (-0.1 -0.2 -0.25) (0.1 0.2 -0.24);
    }
    {
        name    rec_extract;
        type    cellZoneSet;
        action  new;
        source  setToCellZone;
        set     rec_extract;
    }

);

// ************************************************************************* //

I first use topoSet and it shows:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Reading topoSetDict

Time = 0
    mesh not changed.
Created cellSet rec_extract
    Applying source boxToCell
    Adding cells with centre within boxes 1((-0.1 -0.2 -0.25) (0.1 0.2 -0.24))
    cellSet rec_extract now size 14320
Created cellZoneSet rec_extract
    Applying source setToCellZone
    Adding all cells from cellSet rec_extract ...
    cellZoneSet rec_extract now size 14320

End

If I use pimple -postProcess, then I can see the correct file "p_rec.raw" with 14630 points under postProcessing/Sampling_rec/0.
Also if I reconstruct the solution first, I can get correct file under postProcessing/Sampling_rec/0.001, postProcessing/Sampling_rec/0.002 ...
But if I run "mpirun -n 36 pimpleFoam -postProcess", the files "p_rec.raw" under postProcessing/Sampling_rec/0.001, postProcessing/Sampling_rec/0.002 ... will have 22395 points. It's much larger than the region I want, and it's also not the whole domain.

Do you have any idea why sampling a specific zone doesn't work in parallel?
Or something I missed?
Thank you in advance!

[jherb]

Perhaps you missed the -parallel option?
Your command should probably look like:

mpirun -n 36 pimpleFoam -postProcess -parallel