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-   -   how to generate cylinder field in cellSetDict? (https://www.cfd-online.com/Forums/openfoam/103356-how-generate-cylinder-field-cellsetdict.html)

Teemo June 18, 2012 10:03

how to generate cylinder field in cellSetDict?
 
Hello,

I would like to generate a floating object with cylinder shape, how should I setup the cellSetDict?

Regards,
T

eysteinn June 18, 2012 11:05

Quote:

Originally Posted by Teemo (Post 367021)
Hello,

I would like to generate a floating object with cylinder shape, how should I setup the cellSetDict?

Regards,
T

This is from OF 1.6-ext:
OpenFOAM-1.6-ext/applications/utilities/mesh/manipulation/cellSet/cellSetDict

Code:

// Name of set to operate on
name c0;

// One of clear/new/invert/add/delete|subset/list
action new;

// Actions to apply to cellSet. These are all the topoSetSource's ending
// in ..ToCell (see the meshTools library).

topoSetSources

    // Select by explicitly providing cell labels
    labelToCell
    {
        value (12 13 56);  // labels of cells
    }

    // Copy elements from cellSet
    cellToCell
    {
        set c1;
    }

    // Cells in cell zone
    zoneToCell
    {
        name ".*Zone";      // Name of cellZone, regular expressions allowed
    }

    // Cells on master or slave side of faceZone
    faceZoneToCell
    {
        name ".*Zone";      // Name of faceZone, regular expressions allowed
        option master;      // master/slave
    }
   
    // Select based on faceSet
    faceToCell
    {
        set f0;            // Name of faceSet

        //option neighbour; // cell with neighbour in faceSet
        //option owner;    //  ,,      owner
        option any;        // cell with any face in faceSet
        //option all;      // cell with all faces in faceSet
    }
    // Select based on pointSet
    pointToCell
    {
        set p0;
        option any;        // cell with any point in pointSet
        //option all;      // cell with all points in pointSet
    }

    // Select based on cellShape
    shapeToCell
    {
        type hex;          // hex/wedge/prism/pyr/tet/tetWedge/splitHex
    }

    // Cells with cell centre within box
    boxToCell
    {
      box  (0 0 0) (1 1 1);
    }

    // Cells with cell centre within box
    // Is skewed, rotated box. Given as origin and three spanning vectors.
    rotatedBoxToCell
    {
      origin  (0.2 0.2 -10);
      i        (0.2 0.2 0);
      j        (-0.2 0.2 0);
      k        (10 10 10);
    }

    // Cells with centre within cylinder
    cylinderToCell
    {
      p1      (0.2 0.2 -10); // start point on cylinder axis
      p2      (0.2 0.2 0);  // end point on cylinder axis
      radius  5.0;
    }

    // Cells with centre within sphere
    sphereToCell
    {
      centre  (0.2 0.2 -10);
      radius  5.0;
    }

    // Cells with cellCentre nearest to coordinates
    nearestToCell
    {
      points ((0 0 0) (1 1 1)(2 2 2));
    }

    // Select based on surface
    surfaceToCell
    {
        file            "www.avl.com-geometry.stl";
        outsidePoints  ((-99 -99 -59));    // definition of outside
        includeCut      false;              // cells cut by surface
        includeInside  false;              // cells not on outside of surf
        includeOutside  false;              // cells on outside of surf
        nearDistance    -1;                // cells with centre near surf
                                            // (set to -1 if not used)
        curvature      0.9;                // cells within nearDistance
                                                                                                    126,1        73%
                                          // (set to -100 if not used)
    }

    // values of field within certain range
    fieldToCell
    {
        fieldName  U;      // Note: uses mag(U) since volVectorField
        min        0.1;
        max        0.5;
    }

    // Mesh region (non-face connected part of (subset of)mesh)
    regionToCell
    {
        set        c0;        // name of cellSet giving mesh subset
        insidePoint (1 2 3);    // point inside region to select
    }

);

cylinderToCell is probably what you are looking for

/Eysteinn

Teemo June 18, 2012 11:16

Thanks very much, I will give it a try with cylinderToCell.

REgards,
T

lilinghan8 July 17, 2012 07:44

Hi Eystein,

I tried cylinderToCell but the shape of the cylinder looked really strangehttps://docs.google.com/drawings/d/1...DW5AXeEmY/edit, could you help me with this?
https://docs.google.com/drawings/d/1...DW5AXeEmY/edit

Regards,
Li

eysteinn July 17, 2012 07:53

Quote:

Originally Posted by lilinghan8 (Post 371877)
Hi Eystein,

I tried cylinderToCell but the shape of the cylinder looked really strangehttps://docs.google.com/drawings/d/1...DW5AXeEmY/edit, could you help me with this?
https://docs.google.com/drawings/d/1...DW5AXeEmY/edit

Regards,
Li

I guess with "strange" you mean that it is not smooth or?
Have you tried to make the cells smaller in this region?
It is possible that the cells in this region are too larger to make it
better "looking".

lilinghan8 July 17, 2012 08:44

Hi again,

The cells you mean is the mesh size around this region or the cylinder size?
I set the shape of the cylinder based on a physical experiment so I can not change the size of it.

Btw, the simulation cashed down at about 3.5s since floating point exception issue, do you have any idea about how to solve it?

Regards,

eysteinn July 17, 2012 10:17

Quote:

Originally Posted by lilinghan8 (Post 371893)
Hi again,

The cells you mean is the mesh size around this region or the cylinder size?
I set the shape of the cylinder based on a physical experiment so I can not change the size of it.

Btw, the simulation cashed down at about 3.5s since floating point exception issue, do you have any idea about how to solve it?

Regards,


What I mean is that your cylinder selection is created from the cell in your domain. So if you have large cells in your domain the cylinder surface will not be smooth.

If you want to create an solid cylinder inside your domain, then it is probably easier to do that using a cad software and mesh everything, including the cylinder.


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