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-   -   GridGen mesh import to Fluent (http://www.cfd-online.com/Forums/fluent/85539-gridgen-mesh-import-fluent.html)

kiter February 28, 2011 20:19

GridGen mesh import to Fluent
 
Hi all,
Is anyone else using Gridgen to generate their mesh and solving it in Fluent?
I am losing a lot of time splitting, merging, fusing, faces and zones to make my mesh ready for a Fluent run. I'm generally interested in external flow (airfoils, ground vehicles, etc)
Is there any way it can be done more efficiently? Gridgen is the only meshing software I have access to.
Thanks, any relevant thoughts are appreciated.

rmatus March 1, 2011 09:59

Tried the tutorials?
 
Hi Kiter:

I'm not sure why you are having to go through so much splitting and merging and other contortions to make a grid with Gridgen. Have you looked at the tutorials that come with it? There are several aerospace applications there that may give you some tips on how to do things more efficiently.

If there are some specific problems you want help with, let me know, and I will see if I can help.

Rick

kiter March 1, 2011 16:09

Hi Rick,
Thaks for watching out for me!
I am actually having to do all the splitting and merging in Fluent once I import my grd file from Gridgen. The problem comes about when my grid has several domains.
My grd file reads in as exterior lines (boundaries) and solids (domains).
When I have several domains, I have to split them and re-join the walls and the boundaries separately, fuse the fluid interfaces, then merge the solids to make the fluid domain a big continuous one from inlet to outlet.
Do you suggest the tutorials because I can merge domains in Gridgen? Even if their dimensions do not match up, but they share a fluid interface?

rmatus March 1, 2011 16:28

Are the domains continuous in Gridgen?
 
Hi Kiter:

I misunderstood. I thought you were splitting and merging in Gridgen, which is why I suggested the Gridgen tutorials.

By default, the grid should show up in Fluent as one fluid zone as long as all your blocks have the same volume condition set in Gridgen.

Is it possible the blocks in Gridgen are not connected to each other? That is the only reason I can think of right now why they would need to be merged once you get to Fluent. You can check this in Gridgen using the Connector Commands, Merge Entities command. That will color code the connectors in the display window according to their topological use: a connector used by only 1 domain will be red, a connector used by exactly 2 domains will be blue, and a connector used by more than 2 domains will be yellow. If you see red or blue connectors between your blocks, then you know they are not connected.

If that is not it, maybe you could send me a picture of your grid? That may give me some other ideas to try.

Thanks,
Rick

kiter March 1, 2011 18:26

Cool. I will try checking those shared connectors. Let me get back to you...


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