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-   -   [GAMBIT] Mesh problems (http://www.cfd-online.com/Forums/ansys-meshing/76849-mesh-problems.html)

shreyas June 7, 2010 04:49

Mesh problems
 
Hi

I'm currently doing a project related to cfd. I'm supposed to analyze the flow over a 30 cm MAV(micro aerial vehicle) . I use gambit for meshing and fluent for solving. I tried both these methods and dint find them useful:

1) importing a catia model of the MAV(igs) and then trying to make a virtual model by subtracting from a cuboid in gambit.

2) Exporting the subtracted volume as igs and trying to mesh it.

Fluent is not able to recognize the MAV cavity as a boundary condition

What do I do????

shreyas

Chris D June 7, 2010 15:00

What boundary conditions are you using for the "MAV cavity"? If you set the faces that define the cavity as a wall boundary in GAMBIT, then there shouldn't be a problem when you read the grid into FLUENT. What is the error that you're getting?

shreyas June 7, 2010 23:20

Thank you Chris

I have set the faces of the Mav as a wall.....gambit says it has meshed successfully, but when the msh file is imported to fluent it does not recognize the "MAV" wall at all in the "set boundary conditions" list . One thing I noticed is that I could not create a single virtual volume in both the methods of geometry creation described previously. It only allows me to stitch faces to form multiple vrtual volumes.:confused:

Regards
Shreyas

-mAx- June 8, 2010 01:19

sounds weird...
Are you able to see the cavity (display grid)
can you post a picture.

shreyas June 8, 2010 04:03

No, The set of faces i named "MAV" isnt present in any list....whether BC's or display grid. Once I import it to fluent , Only the cube that represents the flow appears with inlet and outlet. I'm quite sure its a problem with the geometry creation.When I import it the edges appear as virtual ones. I then create a cuboid and delete it after unchecking lower geom. option. Then I try to stitch faces...mesh..zones..export.

Wheres the prob

-mAx- June 8, 2010 06:04

In gambit if you click on your "MAV" entity (in the BC list), it is red-shown ? or it is dismissed?
Once you exported your mesh (File/export/mesh) do you have any warning?
In Fluent, if your MAV entities are not present in the BC-list, then it should be included in the default-wall BC created by gambit (you can display this BC) and check if your MAV entity is present.
If not, then you have a problem in your geometry

shreyas June 8, 2010 06:33

The first time I meshed it, the wing edge looked red if i remember clearly. Now its not red. and no it does not appear as default 2d...will try correcting my geometry somehow...thanks


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