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az_f January 17, 2010 21:57

Creating new mesh from existing mesh
I mesh the neck of my model (interface between the T-pipe) with tet/ prism element. Then I delete all the pipes and saved the neck in another file. I opened the ballon like geometry in this file to add the neck. And I mesh this balloon with existing mesh in the neck. But I don't know when I come back to the original file to add the balloon to the pipe the mesh on the neck moved and it's not similar to the previous one. I did tried to use the merge function at the neck but the quality decrease and there are some irrelavent element. Any idea??


-mAx- January 18, 2010 02:18

which software?

az_f January 18, 2010 04:28

I am using ICEM CFD

PSYMN January 18, 2010 12:43

For merging meshes in ICEM CFD, I often start with one full model and save it for each section... Then you can open each copy and delete the parts that are not relevant for that section and mesh the rest.

In the end, you can open the original geometry and load the mesh components (merge, not replace) and then everything should be in the right locations with proper shared boundaries, etc.

I have spelled out the proper procedure a few times on CFD-Online, you can go find on of those postings.

You can also merge meshes that didn't come from the same geometry, but then it is up to you to make sure things are modeled so that the interfaces line up in space and scale. You can always use the "transform" tool to move the geometry into alignment before meshing or move the mesh into alignment if you have already meshed. It is easier at the geometry level because there is a tool to align curves. It will rotate and move to get the geometry aligned based on selected interface curves. Also, if you align the geometry, you will only need to do it once, and not need to repeat each time you adjust the mesh params.


az_f January 18, 2010 19:40

Thanks Simon, I did pretty the same as you said but my problem is at the shared boundaries. when we used merge instead of replace I expect that every nodes and element at the interface merge together and create one element not sitting close togethher with slightly space between. ??? That's because I was trying to use the existing mesh at the interface to mesh the second part. but still there is difference after merging the parts. Could you help me?


PSYMN January 19, 2010 00:12

I have already explained it on CFD-Online.
It is very robust, but the requirements are strict... Look for one of my other posts on this topic... (search my posts for the word "merge", you should find them pretty quick.)

The main two things are a common perimeter and the interface part(s) have to be used only for merging...

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