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-   -   New wall when export to Fluent (https://www.cfd-online.com/Forums/fluent/66708-new-wall-when-export-fluent.html)

hsharbi July 22, 2009 06:46

New wall when export to Fluent
 
Hi everybody,

When I create the mesh in Gambit and export it to I found the new defintion for new wall. The mesh is 3D surrounding a circular cylinder.
I follow different methods to mesh the volumes (based om map and pave) and at the end I defined the B. Layers surrounding the mesh and the cylinder.
Whene I export it I found in Fluent some faces has been difined as wall.
Is that effecty the solution?
Ho wow To remove this new B. llayer difintion?

Apperaicate you advice

Thanks

eseller July 22, 2009 10:19

I have the same problem, Gambit likes to name the 'wall' boundary for some reason ... I don't believes it affects your solution.

If you have any experience working with Fluent, I recently posted a question regarding 'reversed flow' in my simulation, do you have any advice for me?

Thanks and good luck with your simulation!

--E

hsharbi July 22, 2009 10:31

Thanks I will try.
 
Thanks for your reply.

Regarding the reverse flow I face this problem a lot in the 2D but realy I can not remeber how it is deappear.

Also when I try to run the 3D I get the same problem. However, if I have any explanation I will send it to you.

Thanks again

eseller July 22, 2009 10:57

I would very much appreciate any insight you gain in the future concerning this ... I'll be checkin in!

thank you!

hsharbi July 22, 2009 11:00

Wall inside the mesh region
 
Sorry I forget to mention that in my case the created 'walls' are in side the mesh and the case is a circular cylinder with air flow around it, so all boundry layers are open to atmoshpere, but in case of this 'wall' does that effect the flow behavoir specaiily on the vorties shedding behaind the cylinder?

Thanks

eseller July 22, 2009 11:11

I have no experience with that case, but my gut instinct is that it is not a big deal and something Gambit just decides to rename even if when you specify an input.

hsharbi July 22, 2009 13:48

Thank you for quick reply.


I just run the Fluent for 10 iteration and check the results, it treat the 'wall' as wall. In my case I have only the cylinder is a wall while the remaining bounderies are fluid.

What I am sure about is this problem came from concided faces which are created during meshing the volumes. To solve this, ethier user the Face/ Fuse on the FLuent or try to repair it on the Gambit.

This additional remarks for your information.

By the way first rubn I get reverse pressure, but the second one I did not.

I donot know why.

Thanks

-mAx- July 23, 2009 01:29

If you get walls which are not defined from you, then it is certainly a problem with faces which are not connected.
Check their connection

hsharbi July 23, 2009 06:41

Quote:

Originally Posted by -mAx- (Post 223749)
If you get walls which are not defined from you, then it is certainly a problem with faces which are not connected.
Check their connection


Shall I do it in Gambit?

since the Fluent surface/Fuse list does not shown related surfaces.

Thanks

-mAx- July 23, 2009 07:25

yes in Gambit.

hsharbi July 23, 2009 10:49

First, I would to thank every body has been reply to my problem

Second, I solve the problem by doing the following steps in Gambit:

1-Connect the face( ehich they creat the wall in Fluent).

2- If an error( cannot connect because linked meshing. Please remove link) appear just do the following at the begining before connect faces:
a- unlink the faces ( mesh/unlink face meshes)
b-unlink volume (mesh/ unlind volume) which contains the faces.
then you can connect the facee as 1.

Actualy the 'wall' problem has been solved but when I check the grid it has been failed.

Also may important to remmeber that when I scale the grid from 'm' to 'mm' this message appeared ' Warning: non-positive volumes exist.'

Specail thanks to -mAx-, eseller.

-mAx- July 24, 2009 01:12

Then you have another problem with your mesh (independant from your wall's issue)
Chek the skewness / Volume of your mesh with the appropriate icon in Gambit


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