inletOutlet b.c.

vaina74 · July 1, 2010, 09:31

Hi everybody,

I'd like to know something more about inletOutlet condition. If I'm correct, inletOutlet switches U between fixedValue and zeroGradient depending on direction of the flow: is fixedValue if flow direction is the same as patches normal? The patches of my case are outside oriented.
In case of external flow (e.g. a wing), with a 'box' or 'spherical' shape domain, I don't know the flow a priori. have I to set U, $\kappa$ and $\omega$ (for SST $\kappa-\omega$ turbulent model) as:

Code:

    {
        type            inletOutlet;
        inletValue     uniform (Ux Uy Uz);
        value           $internalField;
    }

for U (Ux, Uy and Uz are inlet condition or what? I saw (0,0,0) for outlet condition) and

Code:

    {
         type            inletOutlet;
         inletValue     $internalField;
         value           $internalField;
     }

for $\kappa$ e $\omega$ in ALL external patches?
I'm not sure of inletValue and value meaning (and I also found just inletValue, without value, here).

vaina74 · July 2, 2010, 04:22

I try to explain better my doubts. If I'm right, inletOutlet b.c. act as zero gradient if the flux is going out of a face and acts as fixed value (inletValue) if it's going in on a face.

1. what's the meaning of the parameter value? when is it used?

2. if I don't know inlet or outlet faces a priori (e.g. a wing inside a spherical domain), may I use an inletOutlet condition for the whole boundary surface or something similar?

gfilip · August 20, 2010, 11:24

Hi Vaina,

Were you able to get answers to your questions? I am also curious about the meaning of "value" in the inletOutlet BC.

vaina74 · August 26, 2010, 09:33

Well, I admit I'm not still sure. Nobody answered to this thread and I didn't find anything really exhaustive on internet. So my guesses could be wrong. I'll be grateful to you if you try to open a new, specific thread about this b.c.. Maybe you will be luckier than me.

PS If you have a definitive answer, please, send me a private message

kiran · August 26, 2010, 10:58

hi vaina & gfilip

value in the any boundary condition refers to the uniform(will not change in that bounday) or non uniform(it will vary in that boundary eg; if we want to give boundary layer at the inlet).

hope this gives you better idea for analyzing your problem

Regards
Ambilpur Kiran

vaina74 · August 26, 2010, 11:23

No, I don't think I understood your words

If I'm correct, inletOutlet b.c acts as a fixed value (expressed by inletValue) if flux is going into a face and acts as zeroGradient if flux is going out of a face. But the exact meaning and task of value slips my mind. Indeed I found examples of this kind of b.c. without any value parameter.
I'm interested about that becouse I have to simulate external flows around a wing or similar objects in a spherical domain, without clear inlet or outlet patches.

July 1, 2010, 09:31	inletOutlet b.c.	#1
vaina74 Senior Member Join Date: Feb 2010 Posts: 213 Rep Power: 17	Hi everybody, I'd like to know something more about inletOutlet condition. If I'm correct, inletOutlet switches U between fixedValue and zeroGradient depending on direction of the flow: is fixedValue if flow direction is the same as patches normal? The patches of my case are outside oriented. In case of external flow (e.g. a wing), with a 'box' or 'spherical' shape domain, I don't know the flow a priori. have I to set U, $\kappa$ and $\omega$ (for SST $\kappa-\omega$ turbulent model) as: Code: { type inletOutlet; inletValue uniform (Ux Uy Uz); value $internalField; } for U (Ux, Uy and Uz are inlet condition or what? I saw (0,0,0) for outlet condition) and Code: { type inletOutlet; inletValue $internalField; value $internalField; } for $\kappa$ e $\omega$ in ALL external patches? I'm not sure of inletValue and value meaning (and I also found just inletValue, without value, here).

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July 2, 2010, 04:22		#2
vaina74 Senior Member Join Date: Feb 2010 Posts: 213 Rep Power: 17	I try to explain better my doubts. If I'm right, inletOutlet b.c. act as zero gradient if the flux is going out of a face and acts as fixed value (inletValue) if it's going in on a face. 1. what's the meaning of the parameter value? when is it used? 2. if I don't know inlet or outlet faces a priori (e.g. a wing inside a spherical domain), may I use an inletOutlet condition for the whole boundary surface or something similar?

August 20, 2010, 11:24		#3
gfilip Member Join Date: May 2009 Posts: 54 Rep Power: 16	Hi Vaina, Were you able to get answers to your questions? I am also curious about the meaning of "value" in the inletOutlet BC.

August 26, 2010, 09:33		#4
vaina74 Senior Member Join Date: Feb 2010 Posts: 213 Rep Power: 17	Well, I admit I'm not still sure. Nobody answered to this thread and I didn't find anything really exhaustive on internet. So my guesses could be wrong. I'll be grateful to you if you try to open a new, specific thread about this b.c.. Maybe you will be luckier than me. PS If you have a definitive answer, please, send me a private message

August 26, 2010, 10:58		#5
kiran Member kiran Ambilpur Join Date: Jun 2010 Location: India Posts: 50 Rep Power: 15	hi vaina & gfilip value in the any boundary condition refers to the uniform(will not change in that bounday) or non uniform(it will vary in that boundary eg; if we want to give boundary layer at the inlet). hope this gives you better idea for analyzing your problem Regards Ambilpur Kiran

August 26, 2010, 11:23		#6
vaina74 Senior Member Join Date: Feb 2010 Posts: 213 Rep Power: 17	No, I don't think I understood your words If I'm correct, inletOutlet b.c acts as a fixed value (expressed by inletValue) if flux is going into a face and acts as zeroGradient if flux is going out of a face. But the exact meaning and task of value slips my mind. Indeed I found examples of this kind of b.c. without any value parameter. I'm interested about that becouse I have to simulate external flows around a wing or similar objects in a spherical domain, without clear inlet or outlet patches.