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-   -   [GAMBIT] Split edges? (https://www.cfd-online.com/Forums/ansys-meshing/72877-split-edges.html)

 Zweeper February 20, 2010 05:57

Split edges?

hey,

I'm trying to import some airfoil geometries from pro-engineer as ICES file format and it works good so far.

my problem is that i have just two edges which form the whole wing and therefore i can't create a smooth boundary layer around this airfoil.

I thought now maybe i can solve this problem by splitting my two edges into XX edges. I found a option where i can enter some coordinate values to split edges, but i asked my self if there is also an option to divide the edges with a ratio?

For example: i select 2 edges and i want to split each of them into XX new edges.

I hope you can help me with this.

Regards,
Zweeper

 Zweeper February 21, 2010 11:47

has nobody a clue about that problem?

 -mAx- February 22, 2010 02:57

Sure you can split an edge with a point at a specific ratio.
Split Edge with Point (give your ratio U-Value)

 Zweeper February 22, 2010 07:36

yes, i know this option. but i can just split it with one point.
i want to divide my edge into several (many) single points, if its possible, with an automatic way.

it will take a long long time if i have to split it manual.

 -mAx- February 22, 2010 08:11

Then I don't know, sorry
Maybe it's better to do this in proE
post a picture from ProE, just for curiosity...
You can also import a sketch into gambit, maybe it can help you

 Zweeper February 22, 2010 09:24

1 Attachment(s)
The problem is, i created this geometrie with pro engineer.
But after importing my sketch from pro-e to gambit (iges file) i just have two vertices --> one on the trailing and one on the leading edge of my airfoil profiles.

if i now create an boundary layer, my boundary layer is every time on many parts on the inside of my profiles (and i have negative volumes).

i have no idea how i can solve this problem :(

 -mAx- February 22, 2010 10:40

upload your dbs file on a share server, I will take a look at it tomorrow morning

 Zweeper February 22, 2010 11:33

hey, thats really nice from you.

http://rapidshare.com/files/354266564/GAMBIT.5928.rar

the outer box is the wind tunnel and the inner box around the wings is my interior. the geometry is created in mm and the first boundary layer cell should have an size of 0.0000014.

maybe you could also give me an inspiration for a good mesh for this problem?

kind regards!

 -mAx- February 23, 2010 03:01

1 Attachment(s)
Ok I check your geometry, and you don't need to split your edge into several small ones.
What you need BEFORE applying your BL is to mesh you edges.
Then you don't have any problem (cf: attachment)
If you can spend some tiem on your mesh, you may create a full hexa mesh. But it won't be meshed on the fly (I mean you need surface decomposition, eg: splits)
PS: I didn't use your BL-size restriction, and for info Gambit works without any unity (your mesh has to be scaled in your solver)

 Zweeper February 23, 2010 06:18

okay, so you just meshed the edges, added the boundary layer and meshed then the whole interior right?
but i guess the interval count of the edges has to be very high to provide a good enough accuracy or?

did you used gambit as well?
maybe you can also provide your meshed file on a open host server?

kind regards and thanks so far!

 -mAx- February 23, 2010 07:45

Sure I used Gambit.
It takes really 10min to mesh the center face:
*mesh the airfoil edges with interval 1 (I assume you have to refine especially at the trailing edge)
*create the BL, and adapt the first layer size with your wish
*create a SF with Meshed option, picke the airfoil edges as source, set the growth rate with 1.2 and the max. size with 20 for instance
That's it, and after you may refine your mesh by interacting with SF parameters.

 Zweeper February 23, 2010 16:32

okay, one question, what do you mean with SF? smoothed face? :confused: sry

 -mAx- February 23, 2010 16:36

Size Function

 Zweeper February 24, 2010 06:53

okay thank you, i will try this in the evening! :)

 Zweeper February 25, 2010 15:28

it works perfectly! thanks a lot!

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