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-   -   Meshing a pipe with a hole (http://www.cfd-online.com/Forums/ansys-meshing/88430-meshing-pipe-hole.html)

leekj92 May 17, 2011 11:43

Meshing a pipe with a hole
 
So I exported a surface CAD of a pipe with a hole. I exported it as a parasolid and it seems to work perfectly fine. I am new to ICEM so I am getting sort of confused on this.

I can create a pretty good hex mesh using O-grid blocking strategy, but my concern is making a separate mesh for the hole in the pipe. I am going to export this to fluent, and I need to specify the boundary layers (the hole) and the inlet, outlet of the pipe.

My question might be kind of confusing but any help would be appreciated.

jeevankumarb May 18, 2011 02:40

You need to put the Blocks inside the hole in a saperet part, then you will have saperete mesh fro Hole and Pipe.

PSYMN May 18, 2011 11:53

Do you mean you have a pipe (a cylinder), with a circular patch on the curved side of it that is your inlet? You just need to associate the face with the circle... To do this, make sure you split it out (so you have edges to work with) and then associate the appropriate edges to the perimeter of the hole. The face is automatically associated to the PART of the hole (hopefully a PART you named INLET).

You may also want to add an Ogrid for this hole. Select the block immediatly inside the model (or two or three blocks in that direction if you want). Also select the face of the INLET so the Ogrid will pass out that way. Apply.

Simon

leekj92 May 18, 2011 16:44

1 Attachment(s)
Hi thanks for the help!
I tried your suggestion but I am pretty convinced I am doing something wrong.
I created the first block to associate with the tiny inlet, then merged with a second block that is associated with the bigger inlet and the outlet. I also added an o grid for the tiny inlet and the outlet. The result is in the picture below.. I dont quite understand why it's so irregular...

thanks!

PSYMN May 18, 2011 17:01

It looks like you have two separate blockings (maybe I am just misunderstanding the image)... It looks like you have one for the pipe and one for the hole (The edges for the pipe don't seem to connect with the hole, but rather overlap).

You should have one blocking and then split that blocking to capture the hole...

leekj92 May 18, 2011 17:08

I tried using only block and splitting it. I created the ogrid for the tiny inlet first, then for the big inlet to the outlet. The resulting mesh seems very irregular to me.

saisanthoshm88 May 19, 2011 00:08

Quote:

Originally Posted by leekj92 (Post 308226)
Hi thanks for the help!
I tried your suggestion but I am pretty convinced I am doing something wrong.
I created the first block to associate with the tiny inlet, then merged with a second block that is associated with the bigger inlet and the outlet. I also added an o grid for the tiny inlet and the outlet. The result is in the picture below.. I dont quite understand why it's so irregular...

thanks!

Hi Lee,

Firstly this approach of creating different blocks and then merging them is not appropriate. Build a block , split it accordingly and make necessary associations. Regarding the O- grid thing , try making a single O-grid at a stretch rather than going for separate O-grids. You can select all the blocks at once and then select the faces at the smaller inlet, bigger inlet and the outlet. The O - grid can then run through as desired.

In case you still have problems like some negative quality elements it may be because of the misalignment of some internal O - grid vertices. So then you may want to align them properly and you can even play around with the O - grid offset

PSYMN May 19, 2011 09:31

Right, you should create the Ogrid for the cylinder all at once... But then you can add a second ogrid to capture the inlet boundary as I described earlier.

Try some tutorials to get going faster.

This you tube vid may also help...

http://www.youtube.com/ansysinc#p/u/9/9h97FvWJPcY

Simon

leekj92 May 19, 2011 13:34

thanks for the help!


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