[Ali Blues]

Hi,
In sampling results over surfaces, openfoam allows for using an stl-generated surface. For example in line 312 of $FOAM_UTILITIS/postProcessing/sampling/sample/sampleDict

 triSurfaceSampling   
 {     
    // Sampling on triSurface 
        type        sampledTriSurfaceMesh;      
        surface     integrationPlane.stl;       
        source      boundaryFaces;  // What to sample: cells (nearest cell)        
                           // insideCells (only triangles inside cell)   
                           // boundaryFaces (nearest boundary face)     
    interpolate true;   
  }

I'm currently working on the simulation of an impeller rotating in a cylindrical tank. Prior to applying the above method for sampling on complicated surfaces, I thought of first “validating” it by comparing the results with those obtained by using the cuttingPlane type. Since I have a cylindrical tank, the cutting plane along the cross-section, is a disk. So I made a disk in salome and exported it as stl. Here is the file for surface sampling:

surfaceSampling
{
    type            surfaces;
    functionObjectLibs ("libsampling.so");
    outputControl   outputTime;

    surfaceFormat   vtk;
    fields          (U);

    interpolationScheme cellPoint;

    
    surfaces
    (

     cuttingPlaneBase
     {
        // Cutingplane using iso surface
        type            cuttingPlane;
        planeType       pointAndNormal;
        pointAndNormalDict
        {
            basePoint       (0 0 1);
            normalVector    (0 0 1);
        }
        interpolate     true;

      }

    stlBased
        {
        
        // Sampling on triSurface
        type        sampledTriSurfaceMesh;
        surface     znormal.stl;
        source      cells;  
  
            interpolate     true;

       }


     ); 
  
 }

The results are attached.

As it can be seen the stl approach completely fails. For some reason it doesn't really cut through the cells, rather keeps the original triangles form the stl. In the sampleDict, it's mentioned that the first approach using plane or cutting plane always generates a triangulated surface as well. So now I'm a bit confused as how to deal with this. Is this a bug in the type sampledTriSurfaceMesh which doesn't perform a topoSet analysis automatically? Like creating cellSet from the stl surface? or limitation of the approach or I missed something out?



Thanks
Ali