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-   -   [ICEM] Hole near sharp trailing edge of airplane/wing geometry (http://www.cfd-online.com/Forums/ansys-meshing/79991-hole-near-sharp-trailing-edge-airplane-wing-geometry.html)

jlichtwa September 10, 2010 17:50

Hole near sharp trailing edge of airplane/wing geometry
 
2 Attachment(s)
Hello,

I am meshing an airplane that has a slot at the trailing edge of the wing where the wing upper surface and flap meet (See Fig. 1). There is airflow over the wing as well as from a plenum that exits through the slot and over the flap. The top surface of the slot has a sharp trailing edge with an angle of 13 degrees (approx. the same as NACA 0010, see Fig. 2). When creating my tet mesh, I am continually getting the problem of a hole in the geometry near the sharp trailing edge. Normally there is a blunt lip instead of the sharp trailing edge, and thus this issue does not occur. I wouldnt think this should be a problem, because I know ICEM can handle sharp trailing edges with angles smaller than this. I have used thin cuts, adjusted the edge criterion (as low as 0.0001), and decreased the triangulation tolerance (1e-4), all to no avail. If anyone has any other tips, like possibly decreasing the min size on the different surfaces?, etc... it would be greatly appreciated.

Thanks

jlichtwa September 13, 2010 18:33

Penetrating mesh elements through surfaces
 
I thought I would post a reply to give an update. I have fixed the problem of the hole in the geometry. Now, I have a new problem (its turning into a nightmare though). I think this is because of the small angle near the trailing edge, but the mesh is penetrating through the wing upper surface and onto the upper surface of the slot/plenum. Thankfully, this is happening at a region at the intersection of two surfaces, so I can prescribe curves and points in hopes to get the mesh nodes and edges to attach to this instead of penetrating the surface and joining with the nodes and edges on the other surface which is what is happening now. I had thought to delete the curves in this region, but I need the mesh edges and nodes to be on the curves defining the geometry. When I check the mesh, I get problems such as uncovered faces, penetrating elements, multiple edges, and overlapping elements.

Any ideas?

If this is not making sense to anyone, let me know and I can put up some pictures to show what I am talking about in detail.

PSYMN September 21, 2010 15:19

Edge criterion? Thin Cuts?
 
Pictures always help, but it sounds like you have a thin cuts problem...

You could also reduce your edge criterion and see if that helps?

If you search you can find other posts where I have elaborated on each of these... Or check the help.


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