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Gerrit January 15, 2016 04:31
Meshing of very small parts
 
Hi everyone,

I have a question concerning my next project. It is about a heatet wire in a channel and I want to simulate the heat transfer from the wire (constant temperature) to the fluid, dependent on the fluid composition.
Anyway, at first I want to mesh that. The model is "only" a pipe (approx 10 cm diameter) and a wire in this pipe. The problem is, that the wire has a diameter of 5*10^-6 m.

Has anyone of you already meshed such a small thing like this?

Edit: Might be important to know, that I used blockMesh and snappyHexmesh until now.

Thanks

Best
Gerrit

Gerrit January 22, 2016 09:55
2 Attachment(s)
Hi everyone,

I proceed with my meshing. By splitting my blockMesh into 4 blocks and refine it towards the centre (where the wire is placed) I gained a mesh that represents the geometry very well.


Now I have still one issue: The command checkMesh -meshQuality gives me 703476 cells for the criterion "faces with face pyramid volume < 1e-13".

As my model itself is tiny, the big question is: Does this matter? Isn't this criterion normally used to prevent negative cells?


For the case someone wants to know this is my blockMesh:

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.4.0                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
    (-0.004    -0.004    -0.005)    //0
    (0.004    -0.004    -0.005)    //1
    (0.004    0    -0.005)    //2
    (-0.004    0    -0.005)    //3

    (-0.004    -0.004    0)    //4
    (0.004    -0.004    0)    //5
    (0.004    0    0)    //6
    (-0.004    0    0)    //7

    (-0.004 -0.004 0.005)    //8
    (0.004    -0.004 0.005)    //9
    (0.004    0      0.005)    //10
    (-0.004 0      0.005)    //11

    (0.004    0.004    -0.005)    //12
    (-0.004    0.004    -0.005)    //13
    (0.004    0.004    0)    //14
    (-0.004    0.004    0)    //15
    (0.004    0.004    0.005)    //16
    (-0.004    0.004    0.005)    //17
);

blocks
(
    hex (0 1 2 3 4 5 6 7) (30 15 40) simpleGrading (1 0.5 0.5)       
    hex (4 5 6 7 8 9 10 11) (30 15 40) simpleGrading (1 0.5 2)
    hex (3 2 12 13 7 6 14 15) (30 15 40) simpleGrading (1 2 0.5)
    hex (7 6 14 15 11 10 16 17) (30 15 40) simpleGrading (1 2 2)

  );

edges
(
);

boundary
(
    inlet
    {
        type patch;
        faces
        (
            (0 3 2 1)
            (3 2 12 13)
           
        );
    }

    outlet
    {
        type patch;
        faces
        (
            (8 9 10 11)
            (11 10 16 17)   
        );
    }


    allBoundary
    {
        type patch;
        faces
        (
            (1 5 4 0)       
            (5 9 8 4)
            (12 14 15 13)
            (14 16 17 15)

            (1 2 6 5)
            (5 6 10 9)
            (2 12 14 6)
            (6 14 16 10)

            (0 3 7 4)
            (4 7 11 8)
            (3 13 15 7)
            (7 15 17 11)
                   
        );
    }

   
);

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


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