[me3840]

Hello folks,

After being very frustrated with SHM's results on this test case, I wanted to try CfMesh. I have a pretty simple airfoil which I would like the trailing edge to have sharp features without much refinement.

First, CfMesh seems to only support surfaces with a single size, is this true? I would like the surface to be finer at the LE and TE but along the bulk of the span to be bigger.

Anyway, my main question is at the TE. If I excessively refine the surface (level 5 relative to my max size), I can get a nice sharp edge:
http://imgur.com/8O5LcWU

If I do level 4 it just turns to junk:
http://imgur.com/YZrHXhJ

You can clearly see where the mesh is best aligned with the template it looks great, but when we twist away from that we get garbage. IMO the level 4 is even too fine elsewhere. Is there any way to force the feature edge retention without blowing a million cells on the entire surface? And also preferably without having to define the TE as a separate surface?

[linnemann]

Easiest would be to split the surface in 3 parts. Bulk, LE and TE.

Then you can refined as needed.

You problem is that the TE thickness is lower than the mesh size which is why you have the jagged edges.

You can also zip the case and link here from dropbox, Gdrive etc and I can take a look.

[franjo_j]

Hello,

Originally Posted by me3840

Hello folks,

After being very frustrated with SHM's results on this test case, I wanted to try CfMesh. I have a pretty simple airfoil which I would like the trailing edge to have sharp features without much refinement.

First, CfMesh seems to only support surfaces with a single size, is this true? I would like the surface to be finer at the LE and TE but along the bulk of the span to be bigger.

Anyway, my main question is at the TE. If I excessively refine the surface (level 5 relative to my max size), I can get a nice sharp edge:
http://imgur.com/8O5LcWU

If I do level 4 it just turns to junk:
http://imgur.com/YZrHXhJ

You can clearly see where the mesh is best aligned with the template it looks great, but when we twist away from that we get garbage. IMO the level 4 is even too fine elsewhere. Is there any way to force the feature edge retention without blowing a million cells on the entire surface? And also preferably without having to define the TE as a separate surface?

There are many refinement sources that can help you minimise the number of cells. The one that may be of interest to you are:
1. Edge mesh refinement - create an edge mesh and use it to refine the trailing edge, only. You can generate edge meshes in ParaView or export them from fms by using FMSToSurface utility.
2. Create a refinement region using an object such as a box or a cylinder.

You can find examples in the tutorials folder of the cfMesh source pack.