# [ICEM] Bunching nodes along a curve

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 October 13, 2009, 05:16 [ICEM] Bunching nodes along a curve #1 Senior Member   Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 531 Rep Power: 16 Hi, In the Curve Mesh Setup I have been trying different Bunching Laws and values in the Spacing and Ratio boxes to try and get nodes to bunch together at the centre of a curve. But all my attempts result in node bunching at the curve ends. For example: curve with 100 nodes, Bunching law = BiGeometric, Spacing 1 = Spacing 2 = 0.001 and Ratio 1 = Ratio 2 = 2 gives bunching at the curve ends. So I changed the Ratio 1,2 = 0.5 thinking that would reverse the bunching direction but I it didn't. So how can this be done? Thanks.

 October 14, 2009, 13:51 Bieponential #2 Retired from CFD Online     Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,665 Blog Entries: 1 Rep Power: 39 I just tried it and see what you mean about the BiGeometric not working in that way... It seems like it just goes to uniform if you try it... But the Biexponetial, Hyperbolic and Poisson each worked for me. In my case, I had a curve about 100 units long with size 5 uniform, I set the spacing 1 and 2 to 20 and the ratio 1 and 2 to 0.5... It clearly biased toward the middle at a rate of 2 to 1... I should note that I rarely use this method... If I am going to play with things like this, I would rather use the 2D hexa blocking stuff and just have unstructured patches.

 October 14, 2009, 15:55 #3 Senior Member   Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 531 Rep Power: 16 Thanks again, I'll give that a try when I get back to my CFD PC. Trying the appropriate bunching methods seems a bit hit-an-miss at the moment. Can the equations be given to maybe get a better understanding and see what parameters are used for each method? For example, in one instance I have a curve and I'd like the extreme lefthand and righthand elements to be particular sizes but not sure what method or values of ratio(s) etc needed, without trial-and-error. Although you'd rather use the Hexa blocking, spare a thought for us poor souls who only have tetra/prism .

 October 14, 2009, 15:58 #4 Super Moderator   Ryne Whitehill Join Date: Aug 2009 Posts: 313 Rep Power: 12 I was having the same issue, ICEM seemed to always force the RATIO=2 on me. I ended up using biexponential to distribute my nodes As to the equations, see the help guide. It has all the equations in it

October 14, 2009, 17:42
Help...
#5
Retired from CFD Online

Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
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Right, use the Help...

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