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-   -   [ICEM] Problems with export 2D mesh from ICEM to FLUENT (https://www.cfd-online.com/Forums/ansys-meshing/83958-problems-export-2d-mesh-icem-fluent.html)

PSYMN December 12, 2012 17:04

It is usually better to split all the way rather than try to split only selected blocks... It keeps things less messy.

You can always merge blocks later if you need to clean it up.

For the checking options, there may be a tutorial, but you really just need to look in the help to see what each one does.

Bollonga December 12, 2012 17:15

There's only something weird, when I'm connecting curves to edges, inlet and outlet curves seem to be somehow associated. I didn't care for that, but then in fluent I see that there's no inlet boundary, just to outlets! I've tried to fix that with no success... Any suggestions?

PSYMN December 12, 2012 17:52

No idea, it worked properly for me. :confused:

diamondx December 12, 2012 17:55

Quote:

Originally Posted by Bollonga (Post 397256)
There's only something weird, when I'm connecting curves to edges, inlet and outlet curves seem to be somehow associated. I didn't care for that, but then in fluent I see that there's no inlet boundary, just to outlets! I've tried to fix that with no success... Any suggestions?


i think this happens if you do association of multiple edge with multiple curve.

You need to UNGROUP the curve then you will be able to associate each one of them

Bollonga December 13, 2012 02:49

I've managed to unrelate the curves and reassociate them. I've reassigned BC but in fluent Inlet boundary is still as outlet. I've also tried fixing the mesh again with no results. I can continue working with Simon's mesh, but I'd like to learn how to solve that issue. Anymore thing to try?

Thanks a lot guys!

Far December 13, 2012 06:58

What are the issues with your mesh? did you solve them? I assume you are now working with Simon's blocking.

Bollonga December 13, 2012 07:21

Well, I did all the steps Simon told me, and everything went fine untill I loaded the mesh in fluent. The problem is there is no inlet BC, just two outlet BCs. I checked it on Icem and everything was okay. That wasn't happening to Simon's mesh. I can upload the icem files in case you wanna check it out.

https://dl.dropbox.com/u/6986695/PS_12_12.rar

Far December 13, 2012 11:48

Post # 10 & 12
 
I am talking about the blocking issues at post # 10 and 12. Did you solve them or moved with new blocking as suggested by the Simon. Because I just took look on those files (post 12) and worked around half an hour :( and finally found the fault besides the blocking problems as described in detail by Simon. Wanna know the reason :rolleyes:

PS: I have recorded all into one video clip too, where you can see my frustrution :D

Far December 13, 2012 14:17

Quote:

Originally Posted by Bollonga (Post 397332)
Well, I did all the steps Simon told me, and everything went fine untill I loaded the mesh in fluent. The problem is there is no inlet BC, just two outlet BCs. I checked it on Icem and everything was okay. That wasn't happening to Simon's mesh. I can upload the icem files in case you wanna check it out.

https://dl.dropbox.com/u/6986695/PS_12_12.rar


There are lot of problems in the attached ICEM project as already mentioned by Simon. But i worked Ab_initio, I still got problem.........

In which blocking you have the inlet problem? can you attach that?

Far December 13, 2012 15:05

1 Attachment(s)
Check this ....

https://dl.dropbox.com/u/68746918/ballogona.mp4

https://dl.dropbox.com/u/68746918/final.mp4

Bollonga December 14, 2012 03:46

All the problematic files are in the link I posted. I don't know which block was the one causing trouble. I'm sorry for your lost time.

Far December 14, 2012 04:33

1 Attachment(s)
Quote:

First, I noticed that you had the fluid part set to internal wall instead of fluid. You also had a part for internal wall, which you didn't need. (i just un-associated all those edges).
This was problem, which is solved by Simon already.


Then the blocking issues were solved by Simon's six steps

Quote:

To clean this up...

1) Reset index control
2) Split Block => Extend Split => All Edges (you will see the extra splits revealed)
3) Merge Vertices (turn on option to "propagate merge") select a pair of verts that need to be merged away...
4) Confirm "delete station" (this removes the unnecessary indices, you should see the I index Max decrease to "5")
5) fix any lost projections... (this is why you still had an uncovered face, the tiny edge may not have been properly associated).

6) New premesh, new unstructured mesh, check mesh, output (2D), etc.

To undetstand the problem what i did is :

Case A: (https://dl.dropbox.com/u/68746918/ballogona.mp4)

1. Started the blocking from scratch that is I did not use the six steps by Simon. Instead I went o create block > 2d planner block

2. Deleted the unwanted geometric entities such as internal curves and points. Also deleted the symmetry curves and recreated them.

3. Made the splits according to geometry.

4. Associated the all edge to appopriate curves and points to vertices.

5. Edge mesh parameters (roughly specified)

6. Pre-mesh and then unstructured mesh .

7. Solver selection and boundary condition specification as usual.

8. Mesh output and read into Fluent

9. Bingo error. No matching of nodes. Zero nodes. Non positive volume

10. repeated again and again..................... every time failure.

11 Finally went to boundary condition panel and deleted boundary conditions for the Fluid and interior.

12. Got the mesh working. :cool:

Case B: (https://dl.dropbox.com/u/68746918/final.mp4)

1. Deleted boundary conditions, geometry parts and blocking.

2. recreated the some curves.

3. Initialized new blocking, made splits and associated

4. Edge mesh parameters, pre mesh and conversion to unstructured mesh.

5. solver selection, boundary conditions, and output mesh

6. Read in Fluent. Every thing went fine.


PS: Your case had multiple injuries ;)

Bollonga December 14, 2012 05:53

Wow! Thanks a lot Far, people like you make CFD less cryptic!

Far December 14, 2012 06:32

Case 3 - same blocking and same geometry
 
1 Attachment(s)
Here is the case - Minimum changes from original geometry and blocking. (https://dl.dropbox.com/u/68746918/case3.mp4)

Steps:

1. Start ICEM CFD

2. Load first tin and then blocking.

3. edge mesh parameter on the lower symmetry centre edge were set. Just changed scheme to uniform from geometric.

4. Used extend split > all edges.

5. Delete internal curves. Disassociate (remove association) the corresponding edges.

5. recompute pre-mesh, convert to unstructured meshing, boundary conditions (if needed) and output 2d meshing.

6. Read mesh in Fluent.

Bollonga December 19, 2012 07:07

2 Attachment(s)
Hello again guys,

I've been trying a different mesh for the same case but I've encountered some trouble with my blocking edges.
It seems that when more than 4 edges arrive to a vertex there are some extra edges collapsed into the corners which I cannot erase, in the attached picture the edge count is displayed, and there are some extra numbers in the corners.The desired blocks are also shown in a picture.
I've tried to extend split and then merging nodes and erasing extra blocks but it didn't worked, and it messed everything up.

How can I avoid that "collapsed" edges?

Thanks!

Bollonga December 19, 2012 07:37

1 Attachment(s)
I've also checked the faces of each blocks and there are some missing ones, I don't know why. In the picture blocks are pink and faces black.

Far December 19, 2012 09:34

check out this ..........

http://www.youtube.com/watch?v=IuOCRmNyPQM

http://www.youtube.com/watch?v=3bAKfxSL6Es

Bollonga December 19, 2012 16:05

Thanks Far, but I already did a mesh like the one in the videos. The problem isn't this specific mesh but how to solve this "collapsed" edges for any mesh.

Far December 19, 2012 16:11

attach files so that I can take look of them......

Bollonga December 20, 2012 03:06

Hi, vertex 61 is an example of the issue with the edge. I solved the case with a different blocking, but I'd like to know how to solve that. Thanks.

http://dl.dropbox.com/u/6986695/PS_2D_19_12.zip


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