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-   -   Question about Gridgen and structured domains (http://www.cfd-online.com/Forums/pointwise/111838-question-about-gridgen-structured-domains.html)

Kryo January 16, 2013 10:19

Question about Gridgen and structured domains
 
Hi,

im working on a student's project with gridgen v15 and I have a problem:

what i need is shown in the following picture
https://dl.dropbox.com/u/3545765/what.png

What it shows is basically:
Red - Connector
Black and Blue, 2 domains, that need different amounts of nodes on the connector.

Any idea how I can realize this?
I tried with 2 different connectors, lying on each other, which works, but only until I try to extrude both domains into a coherent 3d block.
see it there:
https://dl.dropbox.com/u/3545765/gridgenproblem.png

thanks for your effort!

rmatus January 16, 2013 16:53

Adjacent blocks with differing number of points
 
As you discovered, Gridgen assumes two domains are connected only if they share a connector, which means they both need to have the same number of points along that shared connector.

You might be able to fool Gridgen into giving you what you want by first creating the domains with the same number of points along the connector, so they are connected. Extrude the blocks to get the shape you want, and then redimension one of the blocks to get the number of grid points you want.

Of course, when you do that Gridgen will automatically propagate that change in the number of grid points through all adjacent blocks, which is not what you want. So you have to break the connection between the two blocks before you redimension one. An easy way to do this is to translate one of the blocks a small distance so the connection between blocks is broken. (Make sure you choose "Unlink Blocks" when Gridgen asks if you want to keep the blocks linked after the translation.) After translating (and breaking the connection between the blocks), you can redimension the block how you want and then translate it back to the original position.

Note that Gridgen will not know about any relationship between the blocks after this, so if you want to keep them linked this will not work for you.

Hope this helps.

Rick

Kryo January 16, 2013 17:49

thanks for your answer. Probably I have to find another solution, instead of using different grid points for 2 connected domains^^


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