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-   -   Problem: Mesh generation in blade wheel (http://www.cfd-online.com/Forums/star-ccm/97457-problem-mesh-generation-blade-wheel.html)

Schallah February 17, 2012 09:14

Problem: Mesh generation in blade wheel
 
1 Attachment(s)
Hi,
starccm generate a mesh with bad cells (see attachment).
These bad calls are all in my region "blade wheel" and I think that the prism layers may cause this bad cells.
I use these meshing models:
- Polyhedral Mesher
- Prism Layer Mesher
- Surface Remesher
The Reference Values are:
- Base Size : 100mm
- Number of Prism Layers: 4
- Prism Layer Stretching: 1,5
- Prisem Layer Thickness: Absolute Size: 0,25mm
- Surface Curvature: Basic Curvature: 180
- Surface Growth Rate: 1,3
- Surface Proximitly: #Points in gap: 3; Search Floor: 0
- Surface Size: Relative Minimum Size: 0,1; Relative Target Size: 45
- Tet/Poly Density: Density: 1; Growth Factor: 1
- Tet/Poly Volume Blending: 1
What can I do to avoid this bad prism layer cells?
The problem is that these calls make the Reynolds stress turbulence model diverging. The k-epsilon model or the SST model work great. But I simulate an side channel blower and therefore I need the RSM model.
Thanks

rwryne February 17, 2012 09:34

Can you show us a picture of the volume mesh on the surface of the blades?

Also, have you played with the prism layer settings found under Continua->Mesh->Models->Prism Layer Mesher ?

Specifically try lowering Minimum Thickness Percentage (Maybe start at 5, and try again at 1) and raising Layer Reduction Percentage (you can go all the way up to 99). Also, increasing your Boundary March Angle may help

Schallah February 17, 2012 10:42

2 Attachment(s)
Wow, thanks for the fast response…
The screenshots are attached now. I will test your settings at Monday.

rwryne February 17, 2012 11:20

Quote:

Originally Posted by Schallah (Post 344958)
Wow, thanks for the fast response…
The screenshots are attached now. I will test your settings at Monday.


Those pics help, but I meant pictures of the mesh on the actual surface, not cut planes. Specifically pictures around the thickness of the blade.

Schallah February 21, 2012 04:53

2 Attachment(s)
Quote:

Originally Posted by rwryne (Post 344963)
Those pics help, but I meant pictures of the mesh on the actual surface, not cut planes. Specifically pictures around the thickness of the blade.

Ok, I hope, that the new screenshots are better…


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