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-   -   Please suggest Blocking stretagy (http://www.cfd-online.com/Forums/ansys-meshing/67418-please-suggest-blocking-stretagy.html)

qascapri August 14, 2009 05:00

Please suggest Blocking stretagy
 
3 Attachment(s)
Hello
I want to mesh a block with a 45 degrees inclined rib. I am facing problem in making bloking for it. The mesh seems to converge to a single point. Please suggest some blocking method for this. Attach are a few figures to understand.
Thanks in advance
WAseem

PSYMN August 16, 2009 15:35

Swept blocks?
 
Does it have to be structured or would a swept block meet your needs?

ICEM CFD Hexa can do swept blocks with ogrids, etc.

I (or others) could also suggest a variety of other structured hexa solutions, but none as easy as a swept solution.

You can convert the blocks to swept under blocking => Edit blocks.

qascapri August 17, 2009 05:29

Hello
Thanks for the reply.
Preferably it should be structured.
My aim is to apply periodic conditions to the inlet and outlet.
Please suggest any solution to ´produre a mesh.
Regards
Waseem

qascapri August 17, 2009 09:33

2 Attachment(s)
Hello
I tried with swept option. the pre mesh appears as attahed.
The problem is that, in Fluent when I try to make periodic boundries, it give me an error. With a coarse mesh this error doesnot exists.
Please give me some solution to this.
Regards
Waseem

PSYMN August 20, 2009 17:46

How about this...
 
1 Attachment(s)
Yea, the sweep looks pretty bad...

How about this?

I did it a little differently on the left and right side, but basically, it uses a quarter OGrid (aka Y-Grid) topology swept thru the model.

PSYMN August 20, 2009 17:52

Periodiciyt
 
Oh yea, I don't know about the periodicity issue and don't have time to look into it... Maybe someone else has an idea or you could contact your friendly neighborhood support person.

jsm August 21, 2009 00:44

Hi,

If possible increase length of side faces (non periodic faces). It may help you. But I dont know how is the full geometry. It is just one suggestion came in mind when seeing your geometry.

Otherwise use non conformal periodic boundary condition in Fluent. This will give you results with some what accuracy reduction due to non conformal periodic boundary condition.

qascapri August 21, 2009 06:03

1 Attachment(s)
@PSYMN:
Thanks for the reply.
I am unable to create this Y-grid. I used Y-grid option from blocking => Edit blocks. I selected one of the trangular block but its not created.
I also tried to make Y-grid by splitting the blocks but it looks as you can see in attachment. Split 1 is OK but with split 2, one of the vertices get attach to the point automatically which cannot be changed.
Please can you explain a little how you made the Y-grid.
Thanks for the help.
If this is done, than Fluent will not show any error.
Regards
Waseem

PSYMN August 21, 2009 09:28

Lots of ways...
 
Basicaly, there are several totally different ways to do it, but I will probably do it with split edge and merge vertex. It is hard to describe that method with words.

You could also just collapse each side into a degenerate block (wedge block) by merging the verts at the tight end down to a point... Then delete that degenerate block permantently and create a yblock from the 6 verticies around the "hole"...

If you toss me this or a similar model, I can block it up and create a replay file so you can see how. You can do that privatley if you would prefer.

Simon

qascapri August 21, 2009 09:38

1 Attachment(s)
Hello
Thanks for the support you are giving me..
Attach you can fins the .tin file of the model.
I hope it would be enough for blocking.
If you need something more, I can provide it also.
Looking forward to your responce.
Regards
Waseem

PSYMN August 27, 2009 14:45

Steps.
 
5 Attachment(s)
It took me a little while to get back to this, but I am done now...

I will attach the project file and a replay file...

Should be quick and fun.

Here are the basic steps...

1) add 4 splits and then merge verts to make two wedges

2) Delete the wedges "permanently"

3) Use the Create from Verts option to create Yblocks using the 6 verts left over after deleting the blocks.

4) Split the block to get the depth of the notch.

5) Delete the notch material

7) Associate (I did it along the way) and set sizes.

8) Bonus step... You could create an Ogrid layer along the floor or the notch or where ever you are interested in viscous flow effects... I just did it along the notch, but you can do it however you want...

9) I guess I forgot to make the verts periodic... That is easy though. Ask me if you don't know how.

PSYMN August 27, 2009 14:48

Ogrid step...
 
3 Attachment(s)
Could only upload 5 pics at a time, so here are 3 more showing the mesh without the boundary layer ogrid, and then with the ogrid selection (all the blocks, and all the faces except for those surfaces you want to inflate), and finally the Ogrid mesh...

From here you would adjust sizes for better resolution, transition, etc.

PSYMN August 27, 2009 14:50

Last but not least...
 
1 Attachment(s)
And last but not least,

The ICEM CFD files and replay file...

You can watch step by step to see how I did it...

It just took a few minutes ( I forgot to time it ).

Simon

qascapri August 28, 2009 06:00

Hello
Thanks for the great effort and support.
This will indeed help me.
Regards
Waseem


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