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-   -   motionU file (http://www.cfd-online.com/Forums/openfoam/114698-motionu-file.html)

sasanghomi March 15, 2013 13:19

motionU file
 
Hi foamers ,

What is motionU file ?? I think it used for cases with dynamic mesh.....
My second question is about componentMixed type that used for the piston in the below motionU file..what is componentMixed type ??what is ref value and value fraction???

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM Extend Project: Open source CFD        |
|  \\    /  O peration    | Version:  1.6-ext                              |
|  \\  /    A nd          | Web:      www.extend-project.de                |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      tetPointVectorField;
    location    "0";
    object      motionU;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField  uniform (0 0 0);

boundaryField
{
    piston
    {
      type            componentMixed;
        refValue        uniform (0 0 0);
        valueFraction  uniform (0 0 1);

    }
    liner
    {
        type            componentMixed;
        refValue        uniform (0 0 0);
        valueFraction  uniform (1 1 0);
    }
    cylinderHead
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    intakePort
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    presin
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    exhaustPort
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    presout
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    valveCurtainCyl1
    {
        type            componentMixed;
        refValue        uniform (0 0 0);
        valueFraction  uniform (1 1 0);
    }
    valve1
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    valve2
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    valveCurtainPort1
    {
        type            zeroGradient;
    }
    valveDetachCyl1
    {
        type            zeroGradient;
    }
    valveDetachPort1
    {
        type            zeroGradient;
    }
    valveCurtainCyl2
    {
        type            componentMixed;
        refValue        uniform (0 0 0);
        valueFraction  uniform (1 1 0);
    }
    valve3
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    valve4
    {
        type            fixedValue;
        value          uniform (0 0 0);
    }
    valveCurtainPort2
    {
        type            zeroGradient;
    }
    valveDetachCyl2
    {
        type            zeroGradient;
    }
    valveDetachPort2
    {
        type            zeroGradient;
    }
    defaultFaces
    {
        type            empty;
    }
}


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

Thanks and best regards,
Sasan.

sasanghomi March 21, 2013 03:30

I appreciate any help.....

ngj March 21, 2013 03:41

Hi Sasan,

The motionU file is related to the laplaceFace-/laplaceCellDecomposition methods, which are only available in OF16-ext. In This file you specify the behaviour of/boundary conditions for the mesh motion.

With respect to the component mixed, then the refValue and valueFraction are specific information needed by this boundary condition. I made a quick search in the source code, however, I cannot figure out what it is doing/which class it is derived from.

Good luck,

Niels

sasanghomi March 21, 2013 05:31

Hi Niels ,
thank you very much.
Sasan.

sasanghomi April 11, 2013 10:25

Hi Niels ,

Can you explain when I should use componentMixed and in this type which direction should be 1 and which one should be 0 ???(for example uniform (1 1 0) )
Actually the motionU file that I attached above is related a 2D engine simulation and I changed the geometry and I created a 3D engine and I want to know what are the boundary conditions in motionU that I must change them?

Thanks and best regards,
Sasan.


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