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-   -   how to avoid self intersection:Proam (http://www.cfd-online.com/Forums/cd-adapco/56477-how-avoid-self-intersection-proam.html)

bala February 29, 2008 06:26

how to avoid self intersection:Proam
 
Hi all,

I am getting self-intersection after generating the subsurface eventhough if i enable avoid self intersection in advanced options. The interesting thing is the self-intersections are not in the subsurface regions but some were in the model. How to avoid this error?

Tom Keheley February 29, 2008 14:04

Re: how to avoid self intersection:Proam
 
Try doing it manually. Select the cells where the self intersecting is happening and change them to a different cell type. Then use the advanced options in the subsurface generation panel to set these cells at a diffent thickness.

Another way is to just set all cells at the lower value, but this will screw up more y+ values. Good luck, Tom

nava March 1, 2008 10:03

Re: how to avoid self intersection:Proam
 
hello Tom & all.

I have the same self-intersecting problem after the sub-surface generation.

I have a duct model, in which i have a sharp corners. after sub surface generation i found that the subsurface is going up and intersecting with surface in the sharp corner.

I have tried playing with advanced options and different cell thickness for the region where i am getting problem. but nothing works the way i excepted.

The one way may be putting the intersecting region to no sub-surfrace. but that doesn't make any sense since the region is very critical to the flow.

Do any one know, how to solve this.?

Regards,

nava

airfoil March 2, 2008 21:13

Re: how to avoid self intersection:Proam
 
Hi all,

Sometimes I also got the same self-intersection error although I knew my shell surface was clean. What I did was, I would do a surface check before I proceed to sub-surface generation. Then I find attach those self-intersection shell and re-create new shell on those area. * To find attached shell, I use this method 1. new vertex set -> cell set 2. new cell set -> vertex set any

Hope this will help!

Airfoil


Andrea March 3, 2008 19:55

Re: how to avoid self intersection:Proam
 
You can also plot a contour plot with surface+subsurface and by that plot you can find intersectiong cell (subsurface menu->Plot...->Subsurface and Thickness Contour). The you can try to remesh the intersecting zone of the surface and then doing a new subsurface or you can change cell type in that zone and create a subsurface with different wall tickness

Anton Lyaskin March 6, 2008 05:23

Re: how to avoid self intersection:Proam
 
In the Advanced Subsurface Options there are two parameters which can help with self intersection problem - number of iterations and relaxation factor.


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