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-   -   [GAMBIT] 3d boundary layer (http://www.cfd-online.com/Forums/ansys-meshing/88796-3d-boundary-layer.html)

truffaldino May 26, 2011 05:29

3d boundary layer
 
1 Attachment(s)
Hello,

I am meshing a segment of 3D wing as shown on the image attached. This is an airfoil in x-y plane translated along z-direction. I have set periodic boundary conditions (linked x-y end faces) in z-direction and set 2d boundary layer(s) on the end x-y plane(s). The wing surface is meshed as quad split.

My question is now: if I mesh the volume around the wing with tet/hybrid, will GAMBIT take those 2d boundary layers into account and create 3d bl zone at the wing surface putting tetrahedra on the top of it afterwards, or it will mesh everythyng with tetrahedra/pyramid instead?

I have tried to mesh it with tet/hybrid, but I could not see the results: If there is an option in gambit which allowes to see bl-part of the mesh (if it exists). I have tried to use standard visualisation of 3D bl, but it does not show anythisng as iI have not created 3D bl.

And another question, even if GAMBIT creates 3D bl, how will it cope with transition between top and bottom 2d bl at the trailing edge (see image)?

Will be grateful for your help.

Truffaldino

-mAx- May 27, 2011 03:13

for 3d domain, create 3d BL.
Just pickt surfaces instead of edges in the BL panel

truffaldino May 27, 2011 03:58

2 Attachment(s)
Quote:

Originally Posted by -mAx- (Post 309452)
for 3d domain, create 3d BL.
Just pickt surfaces instead of edges in the BL panel

Thanks mAx,

I have tried this before posting my question, but it does not give good transition between top and bottom bl at the trailing edge.

I have attached images of a good transition between 2d bl at trailing edge, and unacceptable transition in the case of 3d bl attached to the wing surfaces.

If there is a way to mesh 3d domain ising 2d bl on its periodic borders?

Truffaldino

-mAx- May 27, 2011 04:57

1 Attachment(s)
Ok I see.
Try to extrude the trailing edges.
It will create surfaces, which can be used to split your domain.
Then use them to extend your BL over those surfaces.
It will give you a better wake resolution, and should solve your problem.
Attachment 7838

truffaldino May 27, 2011 16:34

Thanks mAx,

I have used your advice, but rounded TE instead of extruding and then applied curvature size function. In this way I can avoid domain splitting and hope to reuse my journal file for multiple-airfoil configurations with minor corrections.

Truffaldino


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