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-   -   About interface,interior,internal (http://www.cfd-online.com/Forums/fluent/28296-about-interface-interior-internal.html)

cfdfans March 11, 2001 09:37

About interface,interior,internal
 
Hello In gambit ,there are interface,intreior and internal in boundary type,I don't konw the usage of them, and the discrimination of them. who can tell me about it . thank you very much.

alain March 15, 2001 06:03

Re: About interface,interior,internal
 
Hello,

the interface condition is needed for connecting different grid in a model : non matching interface, sliding mesh interface, and so on

the interior condition is usefull if you have surfaces in you model which are part of the fluid. If you don't use interior condition gambit can considerer them as wall.

the internal condition is quite the same as interior but it will be merge in the adjacent interiors in the final mesh if you use tgrid. I think that this condition is useless if you use gambit

best regards.

Alain

Harry Qiu March 16, 2001 03:53

Re: About interface,interior,internal
 
Hello Alain:

I' sorry, I don't understand What "different grid in a model", "non matching interface"and "sliding mesh interface" mean. Could you give me an example respectively?

Thank you very much!

Sincerely yours, Harry Qiu.

Harry Qiu March 16, 2001 03:55

To Alain--About interface,interior,internal
 
Hello Alain:

I' sorry, I don't understand What "different grid in a model", "non matching interface"and "sliding mesh interface" mean. Could you give me an example respectively?

Thank you very much!

Sincerely yours, Harry Qiu.


alain March 16, 2001 05:17

Re: To Alain--About interface,interior,internal
 
hello harry,

I can try to explain what i mean but actuelly it will be simpler with a draw !

Sliding mesh interface : use in the sliding mesh model, one part of the mesh will move regarding to the other.

Different grid interface : for connecting different kind of grid without transition. for exemple, hexa with tetra without pyramidal element. Fluent interpolate the result a mesh interface from one grid to the other.

Non matching interface : grid with diferent shape and/or with different position of their nodes. If you have the fluent tutorials take a look at the film cooling exemple.

I hope this could help you

With my best regards

Alain

Harry Qiu March 16, 2001 06:31

Re: To Alain--About interface,interior,internal
 
Hi, Alain:

Thank you very much for your perfect answer last time. But, I have another question.I'm calculating a laminar premixed gas combustion. I have two questions:

(1)I employed the "finite rate reaction model" for simulating gaseous combustion and "DO radiation model" for modeling radiation heat transfer. When I only simulate cold flow, it quite easy to convergence. But it become very difficult(or impossible)to convergence once I add the reaction and radiation, even though I do it according to the FLUENT 5 Documentaton(Two steps cold-flow-->hot-flow simulation, under-relaxation, patching an ignition). Can you tell me whatever other measures I can take for convergence?

(2)When I patch a "spark" in the fluid zone, the position(location) of reaction front is not the same as I expected preveously. So, does the position of the reaction front(laminar premixed combustion) vary with where the "spark" is patched?

Looking forward to your answer! Thank you very much!

Sincerely yours, Harry Qiu.

cfdfans March 16, 2001 07:56

Re: To Alain--About interface,interior,internal
 
hi Alain

thank you very much. If I set up the 2D(3D)model contain 2 faces(volums) and the fluid will go throuth faces(volums). Do the 2 faces(volums) need to share 1 line(face) and set the line(face) interior.

thank you very much

Harry Qiu March 16, 2001 22:23

Re: To Alain--About interface,interior,internal
 
Hi,

You only introduce your geometry model.Can you introduce your physical background? Why the fluid need to flow through the line(face)?You can read Gambit tutorial guide further.

Harry Qiu


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