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[ICEM] Unstructured 3d blade grid

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Old   October 31, 2011, 13:42
Default Unstructured 3d blade grid
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Papis
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Hi all,
I am trying to make an unstructured tetrahedron mesh of a rotating blade.
The problem I need to simulate is the Caradonna rotor which is a 2 bladed helicopter rotor.

As you can see from the pictured below i have generated an mesh with periodic boundaries.My main problem is the generation of grid ON the blade
As you can see the surface mesh doesn't actually fits the surface of the blade(Not all nodes of boundary faces are on the airfoil surface) which of course is problematic.

At first I thought it might be resolution but when doing hexagonal grids(with blocking for example) the surface is fitted very nicely even at low resolutions.

If anyone could point me to the right direction to understand this issue I would be grateful.
[IMG]file:///home/papis/Desktop/screen1.jpg[/IMG]
[IMG]file:///home/papis/Desktop/screen2.jpg[/IMG]



P.S. I have created only one body (the region between the blade and the outer boundary,since i do not need grid inside the blade)

Thanks a lot
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Old   November 1, 2011, 07:18
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Is it possible that surface meshes should be generated first?
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Old   November 1, 2011, 12:54
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Ludvik Lanicek
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Try decrease "Edge criterion" parameters from 0.2 to 0.005 (Global Mesh Parameters > Volume Meshing (Octree) ) and/or try to use "Thin Cuts".
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Old   November 1, 2011, 14:08
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Yeap this improved things.Thanks a lot for you help.I read the help about the edge criterion option and it wrote " value 0.2 is adequate for most cases.".This is very misleading since 0.2 can't prescribe the surface of naca0012 blade.

Anyway's Thank a lot for your reply Ludvik
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