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[GAMBIT] Sector of a Cylinder

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Old   August 7, 2017, 15:31
Default Sector of a Cylinder
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Hello everybody,
Can any one tell me how to draw and mesh a 30 degree sector of a cylinder in gambit, that has the best meshing quality for CFD simulations?
Thanks in advance
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Old   August 8, 2017, 01:10
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At least follow one tutorial:
https://www.sharcnet.ca/Software/Gam...guide/tg01.htm
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Old   August 8, 2017, 04:55
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Quote:
Originally Posted by -mAx- View Post
Thanks for your reply.
But I don't want to create a full cylinder geometry, I want to create a 30 degree sector of a cylinder and my problem is with its' corner mesh. Actually, I don't know what is the best way to mesh the corner.
Oh, how can I attach my images in the topics?!
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Old   August 8, 2017, 04:59
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if you do the tutorials, you will understand how to split geometries.
Then you need to split your cylinder.
You can attach pictures by clicking to "Go Advanced", you will have more options
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Old   August 8, 2017, 05:09
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Quote:
Originally Posted by -mAx- View Post
if you do the tutorials, you will understand how to split geometries.
Then you need to split your cylinder.
You can attach pictures by clicking to "Go Advanced", you will have more options
Ok, can you say exactly how can I split my 30 degree sector?
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Old   August 8, 2017, 05:11
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CylinderSector2.jpg

CylinderSector1.jpg

Finally, I could attach my pics
Please take a look at these photos
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Old   August 8, 2017, 05:13
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*Again if you do the tutorials you will understand how it works: in your case, create your cylider, create one plane, create another plane with your angle.
Split your volume with both planes.
That's it

*You have the attachment icon, next to the smiley
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Old   August 8, 2017, 05:25
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Quote:
Originally Posted by -mAx- View Post
*Again if you do the tutorials you will understand how it works: in your case, create your cylider, create one plane, create another plane with your angle.
Split your volume with both planes.
That's it

*You have the attachment icon, next to the smiley
Thanks for your help.
As I understand, you mean I create a full cylinder and use an O grid mesh for it, then split it with two planes with an angle of 30 degrees between them. Am I right?
which tutorials can help me through this?
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Old   August 8, 2017, 05:32
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what you did is also ok.
You just need to recreate the volume, because, you only have one surface, and the edges.
But because you already started with the decomposition for your mesh, you will have some work for recreating all the volumes.
That's why I would recommend to start from volume, and then split
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Old   August 8, 2017, 06:27
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Quote:
Originally Posted by -mAx- View Post
what you did is also ok.
You just need to recreate the volume, because, you only have one surface, and the edges.
But because you already started with the decomposition for your mesh, you will have some work for recreating all the volumes.
That's why I would recommend to start from volume, and then split
Shall I mesh the cylinder like this? then split it?
mesh.jpg
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Old   August 8, 2017, 06:42
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No,
Split first, then Mesh (If you split a volume which is already meshed, the mesh will be deleted)
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Old   August 8, 2017, 13:26
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Originally Posted by -mAx- View Post
No,
Split first, then Mesh (If you split a volume which is already meshed, the mesh will be deleted)
Thanks, then let me try it
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Old   August 13, 2017, 04:01
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Prob1.jpg

Prob2.jpgHello Maxime,
I have created a sector of a cylinder and meshed it.
Now, when I am defining boundary conditions it says there are errors especially when I export the mesh for fluent it says it hadn't written the boundary for axis!

Also, I want this mesh for openfoam and I don't know how to define openfoam boundary conditions in Gambit!

I am attaching the type of error I receive when exporting the mesh!

Last edited by omid20110; August 13, 2017 at 07:22.
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Old   August 14, 2017, 00:58
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Check if the edge defining your axis belongs to a surface.
For that just try to pick et delete the edge.
If you are able to delete it, then your edge isn't connected to any surface, which mean you have another edge at the same place, and you picked the wrong one.
In 3d you don't need any axis Boundary, since the "rotation" will be defined with the periodic BC.
Finally for importing Gambit Mesh into OpenFOAM you don't need anything special from Gambit.
Just use Fluen3DMeshToFoam
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Old   August 14, 2017, 06:53
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Quote:
Originally Posted by -mAx- View Post
Check if the edge defining your axis belongs to a surface.
For that just try to pick et delete the edge.
If you are able to delete it, then your edge isn't connected to any surface, which mean you have another edge at the same place, and you picked the wrong one.
In 3d you don't need any axis Boundary, since the "rotation" will be defined with the periodic BC.
Finally for importing Gambit Mesh into OpenFOAM you don't need anything special from Gambit.
Just use Fluen3DMeshToFoam
I tried to delete the edge but it said: It can not be deleted because it is being referenced by upper topology entity!
As you can see in the photos the AXIS edge is being referenced by the two front and back faces.

You mean that in 3d cases I don't need to define any axis boundary?
In openfoam I will use cyclic boundary condition for front and back faces and wall boundary condition for the other faces and an axis edge boundary condition, by the do I need axis for this geometry or not?
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Old   August 14, 2017, 06:57
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in 3d, you don't need any axis BC (also in OF)
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Old   August 14, 2017, 07:07
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Quote:
Originally Posted by -mAx- View Post
in 3d, you don't need any axis BC (also in OF)
really?
then why in tutorials they define axis for 3d cases?
May I send you my Gambit file and you take a look at that?
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Old   August 14, 2017, 07:08
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which tutorials?
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Old   August 14, 2017, 07:18
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Quote:
Originally Posted by -mAx- View Post
which tutorials?
I'm not sure but I think I have seen it somewhere!
but if you're sure that there isn't necessity for axis boundary in 3d cases then I will do that.
Dear Maxime, may you have a look at my gambit file?
I really appreciate your help
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Old   August 14, 2017, 07:24
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you only need axis, if you work with 2d axi-symetrics model.
I can check your model if you insist
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