# [ICEM] ICEM 4 O-grids for 4 Cylinder inside a domain

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April 16, 2021, 06:34
ICEM 4 O-grids for 4 Cylinder inside a domain
#1
New Member

ANGELO
Join Date: Jul 2020
Posts: 12
Rep Power: 2
Hi everyone,

I have been working on Icem for almost one year. Currently, I am meshing a geometry which consists of a cylinder with two plates on both sides of it separated by a gap(between the cylinder and each plate). The whole cylinder and the plates are then immersed in a fluid domain covering everything. I want to mesh the fluid domain around the cylinder, the gap and the plates. I need at least 3 O-grids(one for the cylinder, one for the gap and one for the plates). The problem is that when I create each O-grid using the two faces on the top and the bottom surfaces of the fluid domain, the 3 O-grids traverse the whole domain ending up by affecting the whole domain.(See the figures whene the 3 O-grids are affecting the top and the bottom Surfaces of the fluid domain). I want to ask if there is a way to create each O-grid for each block of the cylinder, the plates and the gap without selecting each time the blocks from top to bottom especially that there is only two faces (Top and bottom).

I would really appreciate your help. Its been two weeks trying to have a clear mesh but I couldnt.

Angelo
Attached Images
 Icem 2.jpg (21.8 KB, 7 views) Icem 1.jpg (26.4 KB, 4 views) icem3.jpg (43.7 KB, 6 views)

 April 16, 2021, 09:02 #2 Senior Member   Sebastian Engel Join Date: Jun 2011 Location: Germany Posts: 557 Rep Power: 18 Asking for clarification: the green and blue parts are plates with a non-zero thickness (so not part of the domain)? And the mesh between the plates should be somewhat independent from the mesh at the far sides of the plates?

April 16, 2021, 09:15
#3
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ANGELO
Join Date: Jul 2020
Posts: 12
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The plates have thickness of 8 mm and between the plates and the cylinder there is also a gap of 2mm. I am trying to mesh the fluid around all parts(Cylinder, plates, gap). I tried with 3 O-grids from top to bottom and then associate each one to the cylinder, gap and the plates, respectively but seems not good since its affecting everything. See figures for clarification.

Attached Images
 clarification.jpg (49.7 KB, 5 views) clarification2.JPG.png (33.5 KB, 2 views)

 April 16, 2021, 13:40 #4 Senior Member   Sebastian Engel Join Date: Jun 2011 Location: Germany Posts: 557 Rep Power: 18 I assume you deleted the blocks filling the plates. Moreover, i believe that you might not have deleted the respective blocks permanently. By not deleting a block permanently, it is moved into the part VORFN, which is a part which collect blocks outside of the domain. This moving-only means the adjacent blocks are kept related. So if you add an ogrid between the plates, the blocks still connected via the "deleted" block will receive the same treatment. This might be what you are experiencing. To stop this relation you must delete the the blocks in the plates to separate the free fluid domains on the far sides. If my assumption is correct, the respective blocks are still present in your VORFN part. Delete the respective blocks again, but now permanently. aero_head likes this.

April 16, 2021, 15:08
#5
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ANGELO
Join Date: Jul 2020
Posts: 12
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I deleted the block from inside the plates as well as inside the cylinder. But my problem is that the 3 O-grids are seen on the top surface of the fluid domain as you can see the image. Is it good to select all middle blocks each time I want to create an ogrid or there is another way to select each block representing the part that I want to have an O-grid on it. The problem is that no faces in between the parts so I am forced each time to select the blocks from top to bottom with the faces(Top and bottom). Plz See the figure of the blocking.

Attached Images
 blocks.JPG (100.4 KB, 4 views)

April 16, 2021, 16:16
#6
Senior Member

Sebastian Engel
Join Date: Jun 2011
Location: Germany
Posts: 557
Rep Power: 18
Quote:
 Originally Posted by angelooo I deleted the block from inside the plates as well as inside the cylinder. But my problem is that the 3 O-grids are seen on the top surface of the fluid domain as you can see the image.
Please inspect the delete block dialog. there is a checkbox "delete permanently".
Then inspect the VORFN part whether it looks like a huge o-grid around your domain, or whether the "outside" is still connected to the "inside".

Quote:
 Originally Posted by angelooo Is it good to select all middle blocks each time I want to create an ogrid or there is another way to select each block representing the part that I want to have an O-grid on it.
I still don't get this problem. To create a 3-layered ogrid you have to select some blocks and faces. Your approach is to create 3 separate o-grids. I'd create only 1 ogrid and split it twice in the radial direction. The latter would result in a more organized inner coordinate system which makes it easier to hide blocks via the index control.

Quote:
 Originally Posted by angelooo The problem is that no faces in between the parts so I am forced each time to select the blocks from top to bottom with the faces(Top and bottom). Plz See the figure of the blocking.
I am pretty sure, i don't understand this problem, too, since the presence of blocks inevitably means there are faces for that block as well. If there is a block between the plates, then you should have selectable face there, too.

If you want an axial-only o-grid (4 blocks) in a selected block, then you have to select the faces which should not be extruded. There is no way around this. How should the programm know what you want to do? Although there are a lot of advancements made with machine learning, icem will likely not profit from it at all (due to ansys' strategy).