[Enternald]

Hi all,


I am running into an issue using topoSet. I have created my blockMeshDict:

convertToMeters 1;

// This is a list of all the verticed in our geometry of interest.
vertices
(
//   x       y       z
    (0       0       0)           //0
    (100     0       0)          //1
    (100     100     0)          //2
    (0       100     0)          //3
    (0       0       10)         //4
    (100     0       10)         //5
    (100     100     10)         //6
    (0       100     10)         //7
    (0       0       10)         //8
    (100     0       10)         //9
    (100     100     10)         //10
    (0       100     10)         //11
    (0       0       11)         //12
    (100     0       11)         //13
    (100     100     11)         //14
    (0       100     11)         //15
    (0       0       11)         //16
    (100     0       11)         //17
    (100     100     11)         //18
    (0       100     11)         //19
    (0       0       21)         //20
    (100     0       21)         //21
    (100     100     21)         //22
    (0       100     21)         //23
);

// These are all the 'blocks' in our geometry, for this iteration there are three.
blocks
(
    hex ( 0  1  2  3  4  5  6  7)       vacuum     ( 10  10  50 )    simpleGrading (1 1 1)
    hex ( 8  9  10 11 12 13 14 15)      membrane   ( 50  50  100 )   simpleGrading (1 1 1)
    hex ( 16 17 18 19 20 21 22 23)      oxygen     ( 10  10  50 )    simpleGrading (1 1 1)

);

// Edges is a blank dictionary as they are unnecessary if this iteration.
edges
(
);

// Boundaries is where we define our boundary patches.
boundary
(
    outlet
    {
        type patch;
        faces
        (
            (0 1 5 4)
            (2 6 5 1)
            (2 3 7 6)
            (0 4 7 3)
            (0 3 2 1)
        );
    }
    membraneOut
    {
        type patch;
        faces
        (
            (8 11 10 9)
        );
    }
    membraneWalls
    {
        type patch;
        faces
        (
            (9 13 12 8)
            (9 10 14 13)
            (10 11 15 14)
            (8 12 15 11)
        );
    }
    membraneIn
    {
        type patch;
        faces
        (
            (12 15 14 13)
        );
    }
    inlet
    {
        type patch;
        faces
        (
           (20 21 22 23)
           (18 22 21 17)
           (17 21 20 16)
           (20 23 19 16)
           (18 19 23 22)
        );
    }
 
);

mergePatchPairs
(
);

Then I created a topoSet Dictionary:

actions
(
// The first entry here is to select the relevant cells in our oxygen region.
     {
        name    oxygenCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (100 100 21) (0 0 11);
        }
    }
// The second entry here is to select the relevant cells in our membrane region.
     {
        name    membraneCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (100 100 11) (0 0 10);
        }
     }
// The third entry here is to select the relevant cells in our vacuum region.
    {
       name    vacuumCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (100 100 10) (0 0 0);
        }
    }
);

My problem is that when I run topoSet I receive the following:


Create time

Create polyMesh for time = 0

Reading topoSetDict

Time = 0
mesh not changed.
Created faceSet oxygenCellSet
Applying source boxToCell
Adding cells with center within boxes 1((100 100 21) (0 0 11))
faceSet oxygenCellSet now size 0
Created cellSet membraneCellSet
Applying source boxToCell
Adding cells with center within boxes 1((100 100 11) (0 0 10))
cellSet membraneCellSet now size 0
Created cellSet vacuumCellSet
Applying source boxToCell
Adding cells with center within boxes 1((100 100 10) (0 0 0))
cellSet vacuumCellSet now size 0
End


Can someone help me understand why my CellSet sizes are 0?

[Tobermory]

Have you tried adjusting the coords, so that the first set of coords in the boxToCell are the min values, and the second the max values? As far as I recall, the syntax is

boxToCell (MINX MINY MINZ) (MAXX MAXY MAXZ)

In other words change

box (100 100 21) (0 0 11)

to

box (0 0 11)(100 100 21)

[Enternald]

Thank you for the suggestion, however, it still states that the size is zero! I updated some of the boundary types, I turned the wall boundarys to wall, however, that also did not change anything.

One thing I am noticing though is when I open the geometry in paraFoam I see the following under oxygen - cellZone. Isn't this what I am looking for (its just weird that it is stating no cells are selected but it still appears in paraFoam). I have attached an image of what I see in paraFoam when only allowing the oxygen - cellZone to be viewed.

[NablaDyn]

Hi, I think a checkMesh output might give a hint on a possibly less obvious problem.

[Bloerb]

OpenFOAM has cellSets and cellZones. They are the same, but cellSets are not used during the solver run, cellZones however are. Your blockMesh already creates cellZones for each block you have named:

hex ( 0  1  2  3  4  5  6  7) vacuum  (10  10  50) simpleGrading (1 1 1)
hex ( 8  9  10 11 12 13 14 15) membrane ( 50  50  100) simpleGrading (1 1 1)
hex ( 16 17 18 19 20 21 22 23) oxygen (10  10  50) simpleGrading (1 1 1)

If you want to convert these to cellSets I'd recommend not using boxToCell but rather zoneToCell. This would directly convert your current cellZone to a cellSet. I am however fairly certain that you already have everything you need, or why do you need a cellSet? And as already suggested you need to keep the ordering from minX minY minZ to maxX maxY maxZ for boxToCell.


As already mentioned however the following works as tested by me:

actions
(
// The first entry here is to select the relevant cells in our oxygen region.
     {
        name    oxygenCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (0 0 11) (100 100 21) ;
        }
    }
// The second entry here is to select the relevant cells in our membrane region.
     {
        name    membraneCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (0 0 10) (100 100 11) ;
        }
     }
// The third entry here is to select the relevant cells in our vacuum region.
    {
       name    vacuumCellSet;
        type    cellSet;
        action  new;
        source  boxToCell;
        sourceInfo
        {
            box (0 0 0) (100 100 10) ;
        }
    }
);