Incompatibility between 2 boundary conditions in Pitzdaily case

AirS · October 5, 2009, 12:23

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, 13:43

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, 07:39

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, 23:50

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, 08:16

yes, I think so as well.
thank you.

October 5, 2009, 12:23	Incompatibility between 2 boundary conditions in Pitzdaily case	#1
AirS Member Join Date: Sep 2009 Posts: 45 Rep Power: 17	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!

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October 5, 2009, 13:43		#2
santos Senior Member Jose Luis Santos Join Date: Mar 2009 Location: Portugal Posts: 215 Rep Power: 18	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

October 6, 2009, 07:39		#3
AirS Member Join Date: Sep 2009 Posts: 45 Rep Power: 17	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.

October 9, 2009, 23:50		#4
hhuang84 New Member Huang Join Date: Sep 2009 Posts: 11 Rep Power: 17	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.

October 20, 2009, 08:16		#5
AirS Member Join Date: Sep 2009 Posts: 45 Rep Power: 17	yes, I think so as well. thank you.