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-   -   Meshing between two elipses (http://www.cfd-online.com/Forums/ansys-meshing/80987-meshing-between-two-elipses.html)

dreft October 13, 2010 03:29

Meshing between two elipses
 
Hi , Im doing the mesh between two elipse with boundary layer in the inner one.

I obtain the mesh of the pic below:

http://farm5.static.flickr.com/4039/...82ebf49d_b.jpg

But the quality of the mesh is very bad(Skew>0.6).

Any suggestions ?

-mAx- October 14, 2010 01:40

If your skewness is <0.8, it should be ok (for 2d, quad)
I assume your problem, is more on the aspect ratio (where it is refined). Then insert more nodes on the refined ellipse (the problem will be projected on the other ellispe, but as is it not refined, I assume it is not a point of interest for you)

dreft October 14, 2010 02:53

I saw the skewness right now , and the problem is that I have a lot of mesh with a skew>=0.8 (the picture below)
http://farm5.static.flickr.com/4039/...bc94a23c_b.jpg

If I insert more nodes to do the mesh I obtain exactly the same problem...
About the aspect ratio , how could I improve it?
Thanks in advance.

-mAx- October 14, 2010 02:58

something is weird. I don't see why cells on the right have bad skewness.
Is it 2d or 3d?
Ca you post picture of skewness (from quality 0 till 1) with on (zx) plane (y pointing in your direction)

dreft October 14, 2010 03:12

The problem is 2d , here the pics:

http://farm5.static.flickr.com/4105/...37f71fb4_b.jpg

Skew from 0 to 1:

http://farm5.static.flickr.com/4061/...6608b758_b.jpg

-mAx- October 14, 2010 03:16

sorry I wanted a front view.
Try to remesh your domain by doubling counter nodes on smallest ellipse

dreft October 14, 2010 03:32

Quote:

Originally Posted by -mAx- (Post 279127)
sorry I wanted a front view.
Try to remesh your domain by doubling counter nodes on smallest ellipse

The second one is a front view of two elipses.
The option of doubling the counter nodes doesnt work.

-mAx- October 14, 2010 04:10

ah ok, I understand now.
doubling counter nodes doesn't work or doesn't improve the quality?
Else you will have to split your domain.
It can help you: http://www.cfd-online.com/Forums/ans...ar-domain.html

dreft October 14, 2010 04:17

Quote:

Originally Posted by -mAx- (Post 279137)
ah ok, I understand now.
doubling counter nodes doesn't work or doesn't improve the quality?
Else you will have to split your domain.
It can help you: http://www.cfd-online.com/Forums/ans...ar-domain.html

Doubling the nodes only does an increase of the % of cells with high skew.
I read the other post , but the domain in my case is different...
Im Trying right now with a TRI mesh and it looks better...

-mAx- October 14, 2010 04:20

sure your domain is different, bt the split technics could help you.
If you are free to work with any kind of element, then I would suggest you to work with quad/pave, and apply a Size Fuction on the smallest ellipse. You also have the possibility to attach a Boundary Layer on it.


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