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-   -   [ICEM] Tri-Shell growth ratio (http://www.cfd-online.com/Forums/ansys-meshing/112057-tri-shell-growth-ratio.html)

j_h_86 January 21, 2013 09:27

Tri-Shell growth ratio
 
Hello,

is there an option in ICEM to minimize the standard growth ratio of a "Patch-Independent-All Tri" surface mesh?

Best regards

Far January 21, 2013 09:34

I am also looking for this option. May be size function can help...!!!

BrolY January 22, 2013 02:52

From the documentation for ANSYS ICEM CFD 14.0 :

Tetra Size Ratio
controls the growth (edge length) of tetra mesh as it moves away from the surface.

For Octree Tetra mesh, size transitions are 2 to 1 locally, but you can still affect the transition rate over a larger number of transitions. For example, if the surface size is 2 and the volume size is 64, you may see something size transitions like the following:

Delaunay 2 3 4.5 6.75 10.13 15.19 22.78 34.17 51.26 76.89
Octree 2 2 4 4 8 8 16 32 32 64

If the ratio was 1.5, the big picture would show both the Octree and Delaunay sizes growing at a rate of 1.5, but the Octree method has to fit it to powers of 2 times the smallest size in the model. Also, you can imagine that changing this to 1.4 or 1.6 might not make that much difference to the Octree mesher, at least not for the first few layers, but would directly change the Delaunay progression.

Far January 22, 2013 04:12

Quote:

Originally Posted by j_h_86 (Post 403128)
Hello,

is there an option in ICEM to minimize the standard growth ratio of a "Patch-Independent-All Tri" surface mesh?

Best regards

Quote:

Originally Posted by BrolY (Post 403251)
From the documentation for ANSYS ICEM CFD 14.0 :

Tetra Size Ratio
controls the growth (edge length) of tetra mesh as it moves away from the surface.

For Octree Tetra mesh, size transitions are 2 to 1 locally, but you can still affect the transition rate over a larger number of transitions. For example, if the surface size is 2 and the volume size is 64, you may see something size transitions like the following:

Delaunay 2 3 4.5 6.75 10.13 15.19 22.78 34.17 51.26 76.89
Octree 2 2 4 4 8 8 16 32 32 64

If the ratio was 1.5, the big picture would show both the Octree and Delaunay sizes growing at a rate of 1.5, but the Octree method has to fit it to powers of 2 times the smallest size in the model. Also, you can imagine that changing this to 1.4 or 1.6 might not make that much difference to the Octree mesher, at least not for the first few layers, but would directly change the Delaunay progression.

.

@Broly: Yes it is. But I think he is looking for surface mesh growth.

j_h_86 January 22, 2013 04:25

Quote:

Originally Posted by Far (Post 403257)
.

@Broly: Yes it is. But I think he is looking for surface mesh growth.

Yes, as Far has indicated, I am looking for an option to modify the growth ratio of the surface mesh.

But anyway-thank you Broly for your answer! :)


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