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-   -   separating top surfaces after extruding the 2D mesh (http://www.cfd-online.com/Forums/ansys-meshing/83486-separating-top-surfaces-after-extruding-2d-mesh.html)

Mario-CFD December 30, 2010 16:48

separating top surfaces after extruding the 2D mesh
 
Suppose a simple 2D rectangular geometry which is divided in the middle to have to separate zones with one interface. By keeping the "new top part name" as "inherited" when extrude the whole surface mesh, we can have all top surfaces together in one part. What shall we do to separate these top surfaces and have two individual top surfaces?

PSYMN December 31, 2010 12:53

Selection workaround...
 
Yes, right now "inherited" means to use the volume name for the top surface. That is not ideal by any means. Instead it should use a variant of the original surface element part name...

Anyway, there are two easy work-arounds, this one is the easier of the two because the top surface starts broken into two and it is easy to separate out the volume elements...

A) Use inherited for the new volume part name. This means the volume elements and the top elements will all be in the same part name as the surface elements they were extruded from.

B) Then you can right click on parts => Create Part. Type in the new Part name for FLUID and use the selection tool bar to "select all volume elements" (second to last icon or hotkey 3).

C) If you also want the new top shells to be in unique names, you can right click on Parts again to Create Part, (You may want to turn off all the other parts first so it is easier to select). Type in a new part name (Such as OUTLET), then rotate the model on the screen so you can easily select the elements you want to move into the new part... MMB to apply. Done.

Note; if you play with the "Create Part" or "Add to Part" element selection you will be able to do lots of things (select by polygon or individual selection, etc.)

Mario-CFD January 4, 2011 15:35

3 Attachment(s)
Thanks.

1. In figure-1 (attached), for extruding the 2D mesh, I use the 4th option from the left on the "select mesh elements". Am I choosing the correct option?

2. You said:
++++++++++
B) Then you can right click on parts => Create Part. Type in the new Part name for FLUID and use the selection tool bar to "select all volume elements" (second to last icon or hotkey 3).
++++++++++

For creating the new part, If I select "select all volume elements", and 'apply' it, i will have just one part (as shown in figure-2), instead of two. What should I do to have two distinct volume zones?

By the way, after doing this "create part", I get some unwanted curves. You may check figure-3, I have turned on just the lower geometry inlet to show what exactly i mean.

3. To have unique name for top shells, using right click on "Parts" and the 'Create part', and tried various option to create the outlets, but no luck!
Based on the figure-3, in order to create B-OUTLET, what option must be chosen from the "Select mesh elements"? And what pats should be turned-on/off ?

PSYMN January 8, 2011 16:26

Yes, the 4th option is "Select all". That is a good way to select everything for extrude.

If I assume that you followed my suggestion to set the volume to inherited, then all the volume elements should be in the part of their initial surface mesh. This makes it easy to control which volume elements you display and select, etc.

Instead of using the option to select all the volume elements, you can select visible, or selected or even select by polygon. Here is my suggestion...

1) Turn off all parts. Then turn on the one part that was extruded.
2) Turn off all shells and lines. Turn on the volume elements.
(at this point you should just have the volume elements from one region displayed on the screen)
3) Right click on parts => New Part. Give it a new name (FLUID1) and select all the visible elements (5th icon from the left) or just box select what is on the screen.

4) Adjust display to the next part that was extruded and repeat 4 for the next fluid.


Then handle shells in a similar way... Now when you turn on each part with shells only, you will see a matching pair of sides. Just create a new part and box select the elements on the one side. You may want to orient the model to make this selection easy...


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