Symmetry plane and errors

sherandlock · September 18, 2013, 22:37

I am running a cylinder flow case with icofoam. In the tutorial, it gives a symmetry problem. But now I am running the whole geometry. I set the top and bottom boundary as symmetry plane as in the tutorial. But I got a time step continuity error.

I am a starter for Openfoam and I don't know how to set the boundary conditions in this case. could someone enlighten me on the boundary condition a little bit?

sherandlock · September 18, 2013, 23:42

Attached is my mesh.

I would appreciate your help very much!

sasanghomi · September 19, 2013, 07:23

Hi ,

I have done this simulation. Correct your boundary conditions as follow :

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       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    cylinder
    {
        type            zeroGradient;
    }

    //up
    shadow-6
    {
        type            zeroGradient;
    }

    //down
    periodic
    {
        type            zeroGradient;
    }

    inlet
    {
        type            zeroGradient;
    }

    outlet
    {
        type            fixedValue;
        value            uniform 0;
    }
    frontAndBackPlanes
    {
        type            empty;
    }
    
}

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

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       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    cylinder
    {
        type            fixedValue;
        value            uniform (0 0 0);

    }

    //up
    shadow-6
    {
        type            fixedValue;
        value            uniform (0 0 0);
    }

    //down
    periodic
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    inlet
    {
        type            fixedValue;
        value           uniform (1 0 0);
    }

    outlet
    {
        type            zeroGradient;
    }
    frontAndBackPlanes
    {
        type            empty;
    }
      
}

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

The boundary of circular cylinder is wall It is Not symmetry !!!

Hope this helps.

P.S. Also take a look at this thread :
http://www.cfd-online.com/Forums/ope...-cylinder.html

sherandlock · September 19, 2013, 14:34

Hi sasanghomi,

Thank you very much!

I follow your instruction and have fixed the problem!

Best regards

Sherlock

sherandlock · September 19, 2013, 23:22

Quote:

Originally Posted by sasanghomi

Hi ,

I have done this simulation. Correct your boundary conditions as follow :

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       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    cylinder
    {
        type            zeroGradient;
    }

    //up
    shadow-6
    {
        type            zeroGradient;
    }

    //down
    periodic
    {
        type            zeroGradient;
    }

    inlet
    {
        type            zeroGradient;
    }

    outlet
    {
        type            fixedValue;
        value            uniform 0;
    }
    frontAndBackPlanes
    {
        type            empty;
    }
    
}

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

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       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    cylinder
    {
        type            fixedValue;
        value            uniform (0 0 0);

    }

    //up
    shadow-6
    {
        type            fixedValue;
        value            uniform (0 0 0);
    }

    //down
    periodic
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    inlet
    {
        type            fixedValue;
        value           uniform (1 0 0);
    }

    outlet
    {
        type            zeroGradient;
    }
    frontAndBackPlanes
    {
        type            empty;
    }
      
}

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

The boundary of circular cylinder is wall It is Not symmetry !!!

Hope this helps.

P.S. Also take a look at this thread :
http://www.cfd-online.com/Forums/ope...-cylinder.html

Hi, Sasan,

Is the top and down also type of wall in this case?

I still get numerical problem and I set them all as wall

sasanghomi · September 20, 2013, 04:03

Hi,
Yes , they are walls . your domain should be big.Paste the error command here.

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September 19, 2013, 14:34		#4
sherandlock New Member You Join Date: Sep 2013 Posts: 5 Rep Power: 13	Hi sasanghomi, Thank you very much! I follow your instruction and have fixed the problem! Best regards Sherlock

September 20, 2013, 04:03		#6
sasanghomi Senior Member Sasan Ghomi Join Date: Sep 2012 Location: Denmark Posts: 292 Rep Power: 15	Hi, Yes , they are walls . your domain should be big.Paste the error command here.