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Old   October 22, 2009, 00:42
Question How work with grid interface??
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Hi All,
In Modeling airfoil, I want to just make some variation of Angle of Attack. I hear that Grid Interface can make my job simpler. i read in tutorial of FLUENT there is correlation with TGRID. But i don't understand how it works. can you tell me How to make simulation by using grid interface??
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Old   October 22, 2009, 02:16
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You need to have 2 separated zones which are not connected.
At the interface between the 2 zones, you will have 2 superposed entities (edge for 2d, surface for 3d).
Just define each entity as separated interface. Then in Fluent, define the couple of interfaces (define/interfaces)
In your case, you create a circle around your airfoil, the interfaces will be the 2 superposed circles.
Check Help (11. Modeling Flows Using Sliding and Deforming Meshes)
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Old   October 22, 2009, 12:44
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Thanks For your response. I've tried. But i doesnt work. Here is my file. I jut want to rotate my foil.
http://rapidshare.com/files/29645441...RFACE.rar.html
Thanks for your help!!!
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Old   October 22, 2009, 13:55
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Will check it on Monday
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Old   October 26, 2009, 02:55
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I check the dbs file and it is alright regarding the interface definitition.
So you shouldn't have proble to define them in fluent.
What kinds of error do you get?
2 points on your gambit session.
* your mesh should be refined around your moving body (in your case the mesh get coarser near the body)
*you have to define the rotating domaine (surface) as separated fluid domain, because you will also rotate this region
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Old   October 26, 2009, 05:59
Question I'm not using dynamic meshing!!!
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In my case, i don't use dynamic mesh in rotating things. I use Grid Interface to make my geometry become less than make geometry in each angle of attack. I hear that in ANSYS, I just make 2 geometry to complete my Angle of attack (I mean geometry of circle & rectangle and I just rotate my circle by using grid interface).
I'm sorry if my mesh is very poor. My focus on meshing is objected in quality of meshing. I don't know what is the best meshing!!
Thanks for your help!!
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Old   October 26, 2009, 06:36
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Ah ok, I thought you wanted your airfoil rotating. Sorry.
So you just have to rotate you middle surface in Gambit with your specific angle, and then export your mesh.
I have no idea with Ansys.
Regarding your mesh, and especially your grid interface, the mesh in this region has to be +/- with the same size.
Best mesh is always quad/map, but the question is: can you afford spending many days trying to mesh your model with full hexa.
In your case, don't hesitate you can easy mesh your stuff with hexa
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Old   October 26, 2009, 07:36
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yes, I'll try it!
In this problem, I use 2D solver. By the way, what is the meaning of "Regarding your mesh, and especially your grid interface, the mesh in this region has to be +/- with the same size"??
Is it meaning that the meshing of interface one and other must similar??
thank you very much!!
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Old   October 26, 2009, 07:44
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not exactily similar, but not 5x bigger (resp. smaller).
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Old   October 27, 2009, 05:58
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I'll try it.
Anyway, do you know the basic calculation of FLUENT in computing Lift Coefficient in 2D?? because There is no Area in 2D.
Thank you!!
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Old   October 27, 2009, 06:35
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I assume you have to enter a reference length in place of the area.
The coeff will be still dimensionless, as the force is computed on an edge (and not a surface)
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Old   October 28, 2009, 22:48
Question what is voume statistic in FLUENT 2D
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Thanks, by the way. when i use FLUENT 2D there is volume statistics when i check my *.msh. what is that?? I have thought before that the value of Cl based on that volume.
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Old   October 29, 2009, 02:56
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check Mesh is only informations about your mesh topology/quality/etc...
No link with Cl
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