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Old   September 12, 2007, 08:08
Default Mesh: Surfaces not connected
  #1
Babs
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Hi all,

The model I'm working on has been imported from cad. I've already cleaned the geometry (merged the edges) but some surfaces dont share the same edges..

On this photo for example...
the upper limit of surface #2 is made of numerous edges 1,2,3,4,5... while the lower limit of surface 1 is made by one edge (behind 1,2,3...)

I tried to merge 1,2,3,4,5... into one virtual edge, but then I can't connect this one to the one from surface 1 (hope i'm clear enough..)

Would you have any advice? What could I do, and is it really important for meshing/simulating ?

Thanks a lot

P.S: On the right handside of the photo, the blue lines are linked both to the surfaces 1 and 2.. very strange..
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Old   September 12, 2007, 09:43
Default Re: Mesh: Surfaces not connected
  #2
mAx
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if you get troubles with the edges, delete the surface 2, delete all your edges (1,2,3,4,5) et then reconstruct your surface 2. if you still have problem, put your cad-file on a server, I'll take a look on it
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Old   September 12, 2007, 10:09
Default Re: Mesh: Surfaces not connected
  #3
Babs
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Hi,

Ive already tried to delete the face and the edges 1,2,3.., but as my geometry is virtual, it wouldn't let me create a face there..

Here is my cad file: http://dl.free.fr/ciTWdzGhf/Mk7.zip

Thanks for help!
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Old   September 12, 2007, 11:11
Default Re: Mesh: Surfaces not connected
  #4
chandra manik
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check your cad file, your surface may be crack or skretch.

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Old   September 12, 2007, 11:20
Default Re: Mesh: Surfaces not connected
  #5
Babs
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What do you mean by "surface may be crack or skretch" ?
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Old   September 13, 2007, 08:21
Default Re: Mesh: Surfaces not connected
  #6
Dr. FLow Squad
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Hi Babs. Your CAD geometry is quite poor. I have looked into it and I tried to mesh it myself. Since the geometry is filled with cracks and gaps I stayed away from Gambit and turned into ICEM CFD TETRA instead which works better with poor CAD. I managed to come up with decent mesh, using only 1 hour work. I've attached some plots of it so you can see the details of it. There are also 10 layers of prism cells around the fuselage, and I created a large box around it to generate the fluid volume. Also the wake is refined. The total number of elements is 720,000.

<center> </center> -Dr. Flow Squad http://tinyurl.com/2gkjh8

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Old   September 13, 2007, 09:04
Default Re: Mesh: Surfaces not connected
  #7
Cyril
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Oh... good job!

But the problem is that I only have gambit... do you have any advice to avoid having poor cad? (I made my cad with solid works)

thanks
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Old   September 14, 2007, 03:13
Default Re: Mesh: Surfaces not connected
  #8
Dr. FLow Squad
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And here it is after running in Fluent. "Funny" Fluctuating Pressure Distribution.

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Old   September 17, 2007, 05:29
Default Re: Mesh: Surfaces not connected
  #9
chandra manik
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Dear Babs you should check your geometry, for cad like your, better you creeate your CAD by surface not by substract your volume by onother volume, my experienced proof if we substract streeam line face by substrac to volume it will be hard, take a look in PRO-E to make surface profil or other CAD

Regards

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