# Boundary Condition

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September 24, 2013, 18:17
Boundary Condition
#1
Senior Member

kumar
Join Date: Nov 2011
Posts: 115
Rep Power: 6
Dear Max,
I am doing wing analysis, Kindly see the image 1 the outer domain has velocity inlet (orange color) & pressure outlet (violet color) and remaining face in outer domain are symmetry. Up to this, BC is ok.
Kindly see the image 2, in that blue color face shows my wing(no thickness-BC is wall) and remaining face I don’t know how to give BC, I give interface for remaining face of both volume 1 and volume 2 but it shows error while run in fluent like there is only one adjacent cell thread.

Kindly help me how I can give boundary condition in volume 1 and volume2 apart from wing face (blue color)please help me.
Attached Images
 Image1.jpg (22.8 KB, 15 views) Image2.jpg (22.7 KB, 15 views)
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kumar

 September 26, 2013, 00:42 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,080 Rep Power: 31 what are volumes 1 and 2? __________________ In memory of my friend Hervé: CFD engineer & freerider

September 26, 2013, 02:18
#3
Senior Member

kumar
Join Date: Nov 2011
Posts: 115
Rep Power: 6
Thanks MAX for coming forward ,

Volume 1 is Left wing and Volume 2 is Right wing.My wing has negligible thickness( like paper), Thats why I project my wing upper, afterwards while connecting all edges to make faces, and then it becomes volume 1 and 2.

I don't how to give BC for this, for both wing surface I give as wall (ie) blue color in that image, and common face between two wing i consider as internal BC ( see the image) and remaining faces I consider as interface. I got error like there is only one adjacent cell thread.

Finally outer domain is considered.

Kindly let me know there is any possibility without project my wing for giving BC & doing meshing. In fluent it does not take the wing while doing without project the wing, It shows only outer domain BC, that's the reason I project my wing.
Attached Images
 Image.jpg (20.7 KB, 5 views)
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kumar

 September 26, 2013, 02:42 #4 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,080 Rep Power: 31 if you consider your wing with 0-thickness, why are you building a wing with thickness? So.... copy both surface wings you want to keep. set visibility (off) of those 2 surfaces (copy) Merge volume1 with outer domain (normally volume 1 should disappear) Merge volume1 with outer domain (normally volume 2 should also disappear, adn you don't see any wing anymore) Set visibility (on) of both copy Now you see your 2 wings with 0-thickness Split outer domain with both surfaces. That's it (if you are handling virtual geometries, it will be more complicated) Let me know __________________ In memory of my friend Hervé: CFD engineer & freerider

September 26, 2013, 03:49
#5
Senior Member

kumar
Join Date: Nov 2011
Posts: 115
Rep Power: 6
Thanks for quick response MAX,

HTML Code:
```if you consider your wing with 0-thickness, why are you building a wing with thickness?
So.... copy both surface wings you want to keep.
set visibility (off) of those 2 surfaces (copy).```
Kindly see the Image 1, I project my wing upper and afterwards I set visibility off.

HTML Code:
`Merge volume1 with outer domain (normally volume 1 should disappear)`
Kindly see the image 2, In that I merge volume 1 with outer Domain(volume 3) I got error like this, Volume 1 cannot be merged with other volume(s) (it is disconnected)

HTML Code:
`Merge volume2 with outer domain (normally volume 2 should also disappear, adn you don't see any wing anymore)`
Kindly see the image 3, In that I merge volume 2 with outer Domain(volume 3) I got error like this, Volume 2 cannot be merged with other volume(s) (it is disconnected)
Attached Images
 Image1.jpg (24.5 KB, 5 views) Image2.jpg (20.6 KB, 5 views) Image3.jpg (20.1 KB, 7 views)
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kumar

 September 26, 2013, 05:07 #6 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,080 Rep Power: 31 *if you copy wing surfaces with (0 0 0), they shouldn't move! *Regarding your errors with merge, try to delete them simply (that would mean volumes are disconnected from outer domain) __________________ In memory of my friend Hervé: CFD engineer & freerider

September 26, 2013, 08:45
#7
Senior Member

kumar
Join Date: Nov 2011
Posts: 115
Rep Power: 6
Thanks max,

I follow your step (kindly see the image4) in that blue color is copied wing (face 62 and face 63) and remaining thing I deleted.

Afterwards, For outer domain I specify boundary types are (velocity inlet-->opposite face--> pressure outlet & remaining faces are symmetry and wing as wall). In specify Continuum types, I select volume from entity tab and I set Fluid. For wing I select face from entity tab and I set Fluid.while export meshing it shows error like

Continuum Entity face fluid does not contain any valid entity and is not written

Continuum or boundary condition specified on entity face62 and face 63 is invalid for fluent6

kindly help me.
Attached Images
 Image 4.jpg (19.4 KB, 5 views)
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kumar

September 26, 2013, 08:56
#8
Senior Member

Daniele
Join Date: Oct 2010
Location: Italy
Posts: 986
Rep Power: 16
Quote:
 Originally Posted by hhh For wing I select face from entity tab and I set Fluid
Delete this continuum condition, as your wing has already be defined as wall, then export the model.

Daniele

 September 27, 2013, 00:32 #9 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,080 Rep Power: 31 this blue color means your surfaces are not connected to the volume. So split the outer domain with surfaces __________________ In memory of my friend Hervé: CFD engineer & freerider

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