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-   -   [ANSYS Meshing] bad mesh (http://www.cfd-online.com/Forums/ansys-meshing/107600-bad-mesh.html)

hadrien51 October 2, 2012 08:50

bad mesh
 
4 Attachment(s)
Hi Everybody
I have a problem with a simple stupid mesh.
It s like a cylinder defined by curves and surfaces.
the surfaces are not touching the edges, I don't know if could be the error
When I produce the mesh, Ansys don't respect the curves and the edges are horrible.

I made lot of thing before posting this thread.
-I clean the geometry
-I set up the max size element to a value and put 0 for the all curves size element
-I set up the max size element to a value and put the same value for all curves size element
-I set up the max size element to a value and put a fine value for all curves size element
I am doing something wrong because ansys have to be capable to mesh this !
any advice ?
thank you

siw October 2, 2012 11:02

You don't say but that looks like ICEM with an octree mesh.

Did you run Build Topology to sort out the connectivity of the geometry?

hadrien51 October 2, 2012 11:10

Hi
yes sorry i forgot to tell that is a octree mesh.
yes also I did Build Topology

siw October 2, 2012 13:25

This is a bit of a longshot, but maybe decrease the Triangulation Tolerance by an order of magnitude (but not too many orders).

hadrien51 October 2, 2012 17:41

hi siw and thank you
what do you mean with "Triangulation Tolerance"
this is an option in octree mesh ?
I saw the post above mine "Octree not respecting curve parameters"
posted by you and now I am trying to use patch dependant but it is not so trivial.
So what do you think ? it is better to follow with octree mesh or passing by patch dependent and delauney
thank you Siw

siw October 3, 2012 02:20

Tri Tol can be found in Settings > Model, but as I said that's a bit of a longshot.

I use the octree method by default as the first step in making a hybrid mesh, I only ever use is as a stepping stone to getting a surface mesh. I then always replace the octree volume mesh by a Delaunay mesh. I've had less success starting with surface mesh - the reason for needing it the other pot is as I need to use autoblock aswell so I need the unstructured tri cells to conformal with the autoblock nodes on adjoining surfaces.

Maybe Far's topic could help http://www.cfd-online.com/Forums/ans...tra-prism.html.

The other alternative is to upload your files and maybe one of the ICEM experts can resolve it.

hadrien51 October 3, 2012 06:33

thank you siw for your wise advice !
I will post my last mesh way if it can help some one

PSYMN October 3, 2012 13:25

Yes, SIW is right... reduce the tri-tolerance by a few orders of magnitude... It will render your geometry more cleanly so Octree has a chance of capturing it.

Not a long shot at all.

If that fails, then try adjusting edge criterion, but it should be enough.

hadrien51 October 4, 2012 10:09

Thank you SIW and PSYMN
It is working perfectly
I decreased by 10 the tri-tolerance and the octree mesh was perfect !
after delaunay and after prism layer
thank you for the support !


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