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-   -   block with 6 vertices (https://www.cfd-online.com/Forums/openfoam-meshing-blockmesh/124440-block-6-vertices.html)

Hale October 5, 2013 04:10

block with 6 vertices
 
1 Attachment(s)
Hi

I'm trying to create a block with 6 vertices. I followed the instruction on page U-142 in the user Guide but I got some strange shape of the block. I guess it is because it assumes that the vertices on the collapsed side have the same y values, which is not the case in my problem.

I have attached a sketch of the geometry. There is no problem defining the 8-cornered blocks at the sides but the 6-cornered blocks are not easy to define if they have to have the right x, y, and z direction as the other 8-cornered blocks.

I tried the following:

8-cornered blocks
hex (7 3 11 15 4 0 8 12)
hex (0 1 9 8 4 5 13 12)
hex (2 6 14 10 1 5 13 9)
hex (7 6 14 15 3 2 10 11)

6-cornered blocks
hex (1 0 8 9 1 2 10 9)
hex (3 2 10 11 3 0 8 11)

This gives the right geometry but when I run the simulation it takes 20 times as much time to get results as when I remove the triangles in the middle and just define a square block!

Am I defining something wrong the two last blocks?

NB. I need these triangular blocks to define a wall in the middle afterwards.

wyldckat October 5, 2013 08:00

Greetings Hale,

If you could provide an example case, it would be easier to experiment this ourselves.

Beyond this, my suggestion is to step back a few steps and use the cavity tutorial as an example for gradually creating collapsed edges. For example:
  1. First split the square-like mesh into 2 triangles.
  2. Then split it again into 4 triangles.
  3. Then finally evolve to the mesh you want.
Best regards,
Bruno


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