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-   -   [GAMBIT] high skew in Gambit (http://www.cfd-online.com/Forums/ansys-meshing/99382-high-skew-gambit.html)

linyx April 2, 2012 10:00

high skew in Gambit
 
1 Attachment(s)
HI everyone

Recently I have a problem in using gambit. I am meshing a 2d airfoil, firstly,I put a boundary layer mesh on the wall, and then use pave/tri mesh to fulfill the rest.But when the resultant mesh come out, there seem an unwanted mesh as shown below. I use some method to smooth it but none of them work. does anybody have the same experience I face now? and what is your solution to it?

Ps: in order to get a relatively good mesh, I set edit> default> mesh> trimesh> lscale method to 3.

andyjo22 April 2, 2012 20:21

Hi linyx,

Do you have a pic of your domain and edge meshing?

I'd advise you to start with a courser boundary layer and edge mesh but it looks as though your mesh has formed through the boundary layer. Let's see your edge meshing and domain and we'll try and fix it

linyx April 2, 2012 22:09

3 Attachment(s)
Quote:

Originally Posted by andyjo22 (Post 352795)
Hi linyx,

Do you have a pic of your domain and edge meshing?

I'd advise you to start with a courser boundary layer and edge mesh but it looks as though your mesh has formed through the boundary layer. Let's see your edge meshing and domain and we'll try and fix it

the msh are as follows, the wing was NACA0018, the first height of boundary layer is e-5*chord, the rows are 30 with growth factor of 1.1.

-mAx- April 3, 2012 01:20

1 Attachment(s)
I would suggest you to split your domain for more control of your mesh.
For instance you can scale your airfoil (copy edge option scale), it will create edges which will surround your airfoil.
Then split your domain with those edges, and finally split the area of trailing edge like the picture.
Attachment 12300
Attach your BL
It will fix your problem, and you will be also able to put a finer layer around your airfoil (not a BL), or even to put a hexa layer

linyx April 3, 2012 07:41

but I wanna know why is this happaning, the pave meshes should be outside of the boundary layer mesh, why in this case some of the tri meshes are attached to the wall? do i need to setup some default?

-mAx- April 3, 2012 07:45

It happened sometimes also with me.
I don't know why.

linyx April 11, 2012 22:41

Quote:

Originally Posted by -mAx- (Post 352817)
I would suggest you to split your domain for more control of your mesh.
For instance you can scale your airfoil (copy edge option scale), it will create edges which will surround your airfoil.
Then split your domain with those edges, and finally split the area of trailing edge like the picture.
Attachment 12300
Attach your BL
It will fix your problem, and you will be also able to put a finer layer around your airfoil (not a BL), or even to put a hexa layer

it is like the offset command in autocad, but in gambit there is no such command like this...


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