Setting zones inside the mesh for source terms

Sets and Zones, can store any mesh entity (point, face or cell) in a data structure that is somewhat similar to a list. The major difference is in the internal handling of the mesh entities, especially in the case of a parallel simulation with topological mesh changes. In this case, the addressing in the list has to be updated accordingly and only the zone provides such a method (use cellZone for this purpose).

• pointSet/faceSet/cellSet provide a named list of point/face/cell indexes. Essentially, it’s just the result of a selection of points/faces/cells, so that you can then do something with them, since you know which ones you want. Usually, these sets are used for data sampling and for creating faceZones or cellZones

• cellZone are an extension to the sets, since zones provide additional information useful for mesh manipulation. Zones are commonly used for MRF, baffles, dynamic meshes, porous mediums and other features available through the dictionary system/fvOptions

Sets can be used to create Zones and vice versa. As a reminder first create a cellSet and then fed the cell set into the creation of the cellZone to use fvOptions

The selection is usually performed by the tools, both of which can select subsets of the mesh and perform boolean operations on them

• setSet → Use an interactive window

• topoSet → Use a dictionary in system/topoSetDict

Two example of topoSet are listed below:

The implementation of 2 cellZones from STL files:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      topoSetDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

actions
(
    {
        name    HE_frontCellSet;
        type    cellSet;
        action  new;
        source  searchableSurfaceToCell;//surfaceToCell;
        surfaceType  triSurfaceMesh;
        surfaceName    HE_front.stl; 
    }
    {
       name HE_front;
       type cellZoneSet;
       action new;          // new cellSet, it doesn't simply add to a previous cellSet
       source setToCellZone;//zoneToCell;
       set  HE_frontCellSet;

    }
    {
        name    HE_frontLateralCellSet;
        type    cellSet;
        action  new;
        source  searchableSurfaceToCell;//surfaceToCell;
        surfaceType  triSurfaceMesh;
        surfaceName    HE_frontLateral.stl; 
    }
    {
       name HE_frontLateral;
       type cellZoneSet;
       action new;   // new cellSet, it doesn't simply add to a previous cellSet
       source setToCellZone;//zoneToCell;
       set  HE_frontLateralCellSet;
    }
);

Implementation of cellZones and faceZones

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      topoSetDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

actions
()
   // FaceZones
    {
        name      baffleSET;
        type      faceSet;
        action    new;
        source    surfaceToCell;
        file      copper.stl;
    }
    {
        name        baffle;
        type        faceZoneSet;
        action      new;
        source      setToFaceZone;
        faceSet     baffleSET;
    }

   // CellZones
    {
        name           notPCB;
        type           cellSet;
        action         new;
        source         zoneToCell;
        zones          ( water air hydrogen);
    }
    {
        name    solid;
        type    cellSet;
        action  new;
        source  boxToCell;
        box     (-1 -1 -1) (1 1 1);
    }
    {
        name    solid;
        type    cellSet;
        action  subtract;
        source  cellToCell;   // select all the cells from given cellSet(s).
        set     notPCB ;
    }
    {
        name    PCB;
        type    cellZoneSet;
        action  new;
        source  setToCellZone;
        set     solid ;
    }

);

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

Delete a zone

To visualize how much Cell Zone there is inside the domain run checkMesh, while if you desire to delete a cellZone, delete the files that topoSet creates in: constant/polyMesh/sets