CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   ANSYS Meshing & Geometry (http://www.cfd-online.com/Forums/ansys-meshing/)
-   -   [ICEM] O-grid strategy (http://www.cfd-online.com/Forums/ansys-meshing/109883-o-grid-strategy.html)

yorelchr November 28, 2012 17:57

O-grid strategy
 
Hello everyone,
I am trying to mesh a part of a geometry. I would like to use the block strategy or even O-block...but I am a bit lost and really "strange things" are coming out.
This is my geometry : http://cjoint.com/?0KCwDA1RElX
I don't know how to divide the domain : I've tried many things with no success.
I have divided the front plane in 9 (3 x 3 with ref to x by y for example) zones and the lateral plane in 6 (2x3 with ref to x by z) zones so that the internal tube is in the ( 2,2,1) zone. But then when I have to associate, I don't know how to proceed: http://cjoint.com/?3KCwWmveoP9

Thank you for any help

yorelchr

Ralen November 29, 2012 01:49

Can you attach the geometry *.tin?

Ralen November 29, 2012 08:14

3 Attachment(s)
I created geometry similar to this.

yorelchr December 1, 2012 09:23

ciao Ralen,

sorry for replying so late, but I had some other work to do and now I'm back again to this geometry. I've tried to send it to you but couldn't...I had the following message "invalid file". Well, I tried to do as you did. And I think I did not too bad. But when I try to read the mesh with Fluent I always have :
Quote:

Error:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: #f

Preparing mesh for display...
Done.
Is there something to do after meshing when using blocks?
I can't see where I'm wrong, the mesh is clean...

yorelchr December 1, 2012 12:16

Here is the geometry with blocking and meshing.
Can anyone tell me what is wrong with it since I can't open the mesh on Fluent.
PS: the mesh is not really good but it's just a try version for testing the compatibility with fluent.

thank you

http://cjoint.com/?3LbrwbsQqX7

Far December 1, 2012 13:30

2 Attachment(s)
Did you specify the periodic in mesh panel. What is the periodicity angle?

yorelchr December 1, 2012 14:01

ciao Far,


thank you for your reply.
I don't understand where I should put parameters for periodicity. In the BC panel I've put periodic but there's no way to specify the value of the angle.
When I do a mesh without blocking, I can read it in Fluent without specifying anything for the periodic surfaces. How can it be?

Far December 1, 2012 14:28

5 Attachment(s)
Minor issues :

1. Quality is low. Needed good topology

2. Current topology can also be improved by putting o-grid inside pipe.

Major issues.

1. Curves and points were part of surface and this is not good for defining the boundary condition. Put curve into seperate part say curves and points into points

2. Periodicity was redefined.

https://dl.dropbox.com/u/68746918/si...lar%20disk.rar

yorelchr December 1, 2012 15:41

1. yes the mesh is quite bad, but it's just for trying (I've spent time yesterday doing a "good" one to realise that Fluent couldn't read it so today I did all the blocking again without taking too much care on meshing).

2. I've put the inside pipe, seems ok for that.

1. About curves and points : I had made 2 parts for that but then ICEM created this "part.00" and put some staff in it: the curves and wall.125 and wall.126... Now I've changed that as you told me. I also checked with the files you've attached. Seems ok.

2. about periodicity: I've created the point (-45, 0,0) as the base point, then axis (1 0 0) with angle 45. But after doing the 4 pairs of points, horizontal lines have appeared as you can see on the picture : http://cjoint.com/?3LbuPedQhPw

And still no way to read the mesh in Fluent.

yorelchr December 2, 2012 06:23

when I do a check geometry, ICEM automatically recreates me this part.00 with curves from the inside pipe and with wall.125 and wall.126. Can it be a problem with that, for example "double curves" ?
When trying to read the mesh in fluent I have also:
Quote:

Warning: Inappropriate zone type (periodic) for one-sided face zone 29.
Changing to wall.
Warning: Inappropriate zone type (periodic) for one-sided face zone 30.
Changing to wall.
Warning: Inappropriate zone type (periodic) for one-sided face zone 31.
Changing to wall.
Warning: Inappropriate zone type (periodic) for one-sided face zone 32.
Changing to wall.
Error:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: #f

Preparing mesh for display...
Done.
Why would there be a problem with these periodic zones? I have given the 45 deg periodicity and created 4 pairs of points...
Any clue?
thanks a lot in advance

yorelchr December 2, 2012 11:14

ok problem solved !!!
when coupling points for periodicity I was taking 4 points not on the same surface but on 2 adjacent surfaces.
thank you very much for your help!!!


All times are GMT -4. The time now is 04:09.