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-   -   Incompatibility between 2 boundary conditions in Pitzdaily case (http://www.cfd-online.com/Forums/openfoam-solving/68888-incompatibility-between-2-boundary-conditions-pitzdaily-case.html)

AirS October 5, 2009 11:23

Incompatibility between 2 boundary conditions in Pitzdaily case
 
Hi all,
I've just noticed something weird in the 0-directory for the velocity U:
We have:

inlet
{
type turbulentInlet;
referenceField uniform (10 0 0);
fluctuationScale (0.02 0.01 0.01);
value uniform (10 0 0);
}

outlet
{
type inletOulet;
inletValue (0 0 0); // I thought it was (10 0 0) no ?
value (0 0 0);
}

Indeed, I can't understand this latter, although the inlet velocity is defined by (10 0 0), we use a different one for the outlet BC.
Does anybody know the reason ?
Moreover I don't know why we have to specify the keyword ''value'' ? besides, in some cases it doesn't appear.
Thank you in advance!

santos October 5, 2009 12:43

Hi,

The inletValue in the inletOutlet boundary condition specifies the inflow velocity at your outlet - normally you want it to be zero to prevent inflow.

Regards,
Jose Santos

AirS October 6, 2009 06:39

Thank you for answering so quickly,
nevertheless, I've seen the documentation for "turbulentInlet" and it doesn't specify anything about the keyword "value", so what is the purpose of it ?
Same question concerning "inletOutlet", because there is no change when we delete it.
regards,
Rom.

hhuang84 October 9, 2009 22:50

By looking at the U file at other time, I think, value specifies the velocity at ascribed path. so, at time 0, the inelt velocity is uniformly 10, but it varies for other time.

AirS October 20, 2009 07:16

yes, I think so as well.
thank you.


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