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-   -   HELP! Periodic Problem (http://www.cfd-online.com/Forums/fluent/99652-help-periodic-problem.html)

foxer April 8, 2012 23:21

HELP! Periodic Problem
 
I'm making a 3D disc. I split it to 24 pieces that is each one is 15. I want to use one piece and periodic conditions to simulate the whole disc. But after meshing with hexa meshes in Icem, I have a problem setting the periodic condition in Fluent. The log is as below:

/mesh/modify-zones> make periodic
Invalid boundary zone.
Periodic zone [()] 29
Shadow zone [()] 30
Rotational periodic? (if no, translational) [yes] y
Create periodic zones? [yes] y

zone 29: matched 0 out of 2237 faces.
zone 30: matched 0 out of 2237 faces.

Error: Failed to make zones periodic.
Error Object: #f

So I tried to mesh on a simple model, and made the periodic surfaces only have 4 faces, and this problem is still there. What should I do?

After that, I tried to set periodic condition in Icem at Set up periodicity in Global Mesh Parameters and Periodic Vertics in Edit Block. When importing this new mesh to Fluent, periodic condition is no longer a problem. But when checking the mesh, it showed as below:

WARNING: translation vector inconsistent on zone 25. Please check periodic setup.
Done.
WARNING: Mesh check failed.

How can I solve these problems? Thank you guys in advance!

Marx June 27, 2012 08:00

Normally there could two reason for this error. First check the origin of your disc. So how do we check, open the design in design modeler then use point entity to check the centre of rotation coordinate. u can even draw on the surface of your model and find the centre of rotation. (anyway works). if its rotating along z axis then get the x and y coordinate and place it in fleunt>cell zone condition> rotation axis origin.

if it does work then maybe its due to different number of cell on the face of the two surface. It a non conformal periodic.(https://www.sharcnet.ca/Software/Flu...ug/node186.htm) you have change the type of B.c from wall to interface then use Mesh Interface where you select the surfaces, check the periodic B.C set the angel offset and create periodic.


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