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-   -   Gaps in between surfaces (https://www.cfd-online.com/Forums/fluent/41150-gaps-between-surfaces.html)

 Vidya Raja May 28, 2006 16:15

Gaps in between surfaces

Hi,

the model that I'm trying to mesh has some small gaps (of the order of 1E-6) at the sites where two surfaces are being merged. I don't want any flow through those gaps. The gaps arose when I did the modeling in Pro/E. Will GAMBIT or Fluent detect those gaps and create problems?

I'm wondering about this because I'm having problems meshing my geometry and GAMBIT does not specificaaly point out to this while giving errors. But during the analysis, will FLUENT detect gaps of such small magnitudes and give erroneous results?

Thanks, Vidya

 jiangxuxu May 28, 2006 21:09

Re: Gaps in between surfaces

Hi,

As far as I know, Gambit and Fluent merely detect the least distance of 0.000001. If the gap is smaller than 0.000001, Gambit and Fluent can't solve.

 Vidya Raja May 28, 2006 21:18

Re: Gaps in between surfaces

Hi,

What do you mean by "Can't solve"? Please explain.

The gap that I detect in Pro/E is about 6.4548*10E-6. So will I get wrong results from my FLUENT analyses? Will there be problems in meshing? I'm trying to fix the problem in Pro/E itself, but am unable to find a solution.

If I go ahead with what I have right now, will GAMBIT and Fluent blow up?

Thnaks, Vidya

 jiangxuxu May 28, 2006 21:31

Re: Gaps in between surfaces

Hi, 'can't solve' means them can't tell aparat(distinguish). 6.4548*10E-6 means 0.000064548. So Fluent and Gambit can compute.

 Kasper Skriver May 29, 2006 08:30

Re: Gaps in between surfaces

Ok, GAMBIT operates with an accuracy of 1E-06 in any kind of units.

Let's say you have a cad(SAT) drawing with a gap below 1E-06, then GAMBIT will not see the gap - and you can continue with no mesh problems.

If the gap is above 1E-06 you got a problem in GAMBIT and need to take care of the gap in some way. Cleanup could be a solution, I would zoom in and detect the error visualy and then create a new volume without gaps.

I don't know if you can change the 1E-06 tolerance in GAMBIT or maybe in your cad program.

/Kasper@DK

 Vidya Raja May 29, 2006 09:37

Re: Gaps in between surfaces

Thanks Jiangxuxu and Kasper. I'll try your suggestions and see how it works.

Cheers, Vidya

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