[GAMBIT] Mesh problems

shreyas · June 7, 2010, 04:49

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.

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

June 7, 2010, 04:49	Mesh problems	#1
shreyas New Member Shreyas Join Date: Jun 2010 Posts: 7 Rep Power: 15	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

June 8, 2010, 01:19		#4
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	sounds weird... Are you able to see the cavity (display grid) can you post a picture. __________________ In memory of my friend Hervé: CFD engineer & freerider

June 8, 2010, 06:04		#6
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	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 __________________ In memory of my friend Hervé: CFD engineer & freerider

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June 7, 2010, 15:00		#2
Chris D Senior Member Chris Join Date: Jul 2009 Location: Ohio, USA Posts: 169 Rep Power: 16	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?

June 7, 2010, 23:20		#3
shreyas New Member Shreyas Join Date: Jun 2010 Posts: 7 Rep Power: 15	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. Regards Shreyas

June 8, 2010, 04:03		#5
shreyas New Member Shreyas Join Date: Jun 2010 Posts: 7 Rep Power: 15	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

June 8, 2010, 06:33		#7
shreyas New Member Shreyas Join Date: Jun 2010 Posts: 7 Rep Power: 15	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