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Velocities exceed limitation value

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Old   September 28, 2018, 11:00
Default Velocities exceed limitation value
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Rouven Künze
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Dear Users,


I started using OpenFoam for open channel flow. I am simulating a river with a free surface using the interfoam solver. For stability reasons I am using the limit velocity option (fvOptions object):


FoamFile
{
version 2.0;
format ascii;
class dictionary;
location system;
object fvOptions;
}

limitU
{
type limitVelocity;
active yes;
selectionMode all;
max 5;
}



My simulations converges and results look ok. However in the airphase I observe velocities larger than 5. Did I use the fvOption incorrect or does anyone has an idea why velocoties in the airphase exceed my max value?


Thank you very much in advance


Rouven

Last edited by Rouvi; October 1, 2018 at 03:48.
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Old   October 1, 2018, 03:47
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Rouven Künze
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Dear Users,


I figured out that my large velocities occur on the upper atmosphere boundary. I am using the folloing set up on this boundary for U:


atmosphere
{
type pressureInletOutletVelocity;
value uniform (0 0 0);
}



and for p_rgh:


atmosphere
{
type totalPressure;
gamma 1.4;
p0 uniform 0;
value uniform 0;
}



So I am wondering if the limiter Option does not address bc and if my problem is related to this thread:



atmospheric boundary condition


Thank's again for any comments.


Rouven
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