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-   -   help with ICEM Meshing (http://www.cfd-online.com/Forums/ansys-meshing/67125-help-icem-meshing.html)

az_f August 4, 2009 21:01

help with ICEM Meshing
 
Hi everybody,
I have a bifurcation model with aneurysm at the middle. I want to do mesh the aneurysm and the pipes separately in ICEM to increase the quality of the mesh. But I don't know how to hide one part in ICEM and mesh the other parts and then joint both mesh together at interface.

Any suggestion will be appreciated.

Thanks

bharath August 4, 2009 22:10

hi,
you should name the parts separately and you can hide it easily.you can make interface between them in PRE.

az_f August 4, 2009 23:36

Thanks for your response. Could you tell me how I can hide the part in ICEM. Do you mean I need to use subset or there is another way. Because when I right click on each part there isn't any option for hiding the part.


Thanks

PSYMN August 5, 2009 08:57

Hide...
 
In the model tree (on the right) you can expand the parts branch. There are check boxes next to each part name... You can just turn parts on or off... There are also options to right click on surfaces and blank them...

But this may not help you to "mesh the pipes separately to increase the quality of the mesh".

How do you think separating them will increase quality? Are you hexa meshing the various sections? Are you planning to hex mesh the aneurysm and tet mesh everything else?

If you give me a better idea of what you are doing, I can suggest a detailed process.

az_f August 5, 2009 17:23

http://www.cfd-online.com/Wiki/Image:B1.jpg

Hi
As you can see in the picture I have a sharp aneurysm in the middle of the tubes with one inlet(250 ml/min) and two outlets. It's a steady-state laminar blood flow. I don't know why the model can not converge. I was thinking if I can mesh the tubes without aneurysm, the program can make a smoother mesh in the tubes and then somehow(I don't know how ) I add the aneurysm with merging the mesh at interface. I used mixed tet/hex mesh with 4 layers prism mesh. The quality of thye mesh after smoothing is 0.35.
I tried to run the model with less amount of inlet and used the results as an inithial value for the next run. but still after a few run the program diverge.

If you have any suggestion, please help me.

http://www.cfd-online.com/Wiki/Image:B1.jpg

Thanks

PSYMN August 6, 2009 10:56

Breaking up may not help...
 
I don't think breaking this model up will help with convergence... It would simply add another level of complication for the solver.

If you wanted to post the geometry and mesh (or send to me privately) I could check the mesh and see if I see any issues.

If the mesh is fine, it may be your boco's that are the problem...

PSYMN August 6, 2009 10:58

Hexa...
 
It would be relatively simple (<15 minutes) to hexa mesh this model... I could give it a first pass if you like...

PSYMN August 10, 2009 14:29

Hexa Mesh was easy...
 
4 Attachment(s)
Here you go (files sent privately)… Since you didn’t give any parameter guidance, I just did a 5 minute quickie job and didn’t try to optimize the mesh or improve quality at all…

One key thing I did was create some ISO Parametric curves and points to help me hang the blocking on your geometry… The rest was very basic Hexa.

I didn't get your actual mesh params, so it may need tweaking, but generally speaking, if ICEM CFD Hexa doesn't converge, you know it is not a mesh problem...

gi12 December 1, 2010 08:55

(Y) shape like tubes
 
Dear all
I presume this an easy issue to you and I would really appreciate if you can help me to hexa meshing my project. I am trying to mesh a (Y) shape like tubes with some sort of asymmetric nature. I am struggling in having a blocking strategy at the bifurcating zone.
Therefore It will be much appreciated if you can advice me meshing the bifurcating zone (
Many Thanks
GI

PSYMN December 1, 2010 11:13

Y Pipe Collapse Blocks.
 
3 Attachment(s)
GI12,

There is a tutorial for this, the Pipe Blade tutorial. In the tutorial you have a blade in a pipe, but you can imagine that half of it is a Y Pipe...

The trick is to collapse blocks... In reality I would probably just use collapse blocks, select the edge to collapse, select all the blocks to collapse and apply (much faster than pinching out all the separate vertex pairs.) If the model were really this simple, this is the method I would always use.

Attachment 5573

But there are lots of ways to do it, and some are helpful in certain situations. Here is the "extrude" method. I only use this when I have no other choice because it tends to clutter the index control (and I use the index control allot).

Attachment 5574

Here are a variety of other methods.

Attachment 5575

Have fun.

PSYMN December 1, 2010 13:54

Survey
 
One more thing...


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