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Free output Velocity - icoFOAM

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Old   March 26, 2013, 15:57
Default Free output Velocity - icoFOAM
  #1
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Elisa
Join Date: Mar 2013
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Hi,
I'm new in OpenFOAM.
I'm running icoFOAM for a Y-geometry (cylinders) but I have this error: "floting point exception". In fact I have a really huge Courant number even if I have a small deltaT (0.00001).

How can I solve this kind of problem?

In addition I'd like to have free velocity in both outlets, any help??

These are my 0\p and 0\U files:

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

internalField uniform 0;

boundaryField
{
inlet
{
type fixedValue;
value uniform 56291.66e5;
}

outlet
{
type fixedValue;
value uniform 56289.67e5;
}

wall
{
type zeroGradient;
}
}

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

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

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (0 0 4.94745);
}

outlet
{
type fixedValue;
value uniform (0 0 1.44048);
}

wall
{
type fixedValue;
value uniform (0 0 0);
}
}

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

Last edited by Guenda; March 26, 2013 at 16:31.
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Old   March 27, 2013, 13:40
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Bernhard Gschaider
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Quote:
Originally Posted by Guenda View Post
Hi,
I'm new in OpenFOAM.
I'm running icoFOAM for a Y-geometry (cylinders) but I have this error: "floting point exception". In fact I have a really huge Courant number even if I have a small deltaT (0.00001).

How can I solve this kind of problem?

In addition I'd like to have free velocity in both outlets, any help??
Just some random remarks: fixing velocity everywhere is almost never a good idea as you'll probably violate mass conservation (I guess that's where your high Courant came from). "free velocity" would be zeroGradient but with what you're trying to do that might be too liberal. Have a look at the tutorial cases.
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Old   March 27, 2013, 14:48
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Elisa
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Now I have a turbolent flow so simpleFoam should be better, does 'zeroGrandient' work for the outlet 'free velocity' in this new case?

Thank you so much.
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