Topic: what's good mesh criterion for Fluent?

liujiangkun · April 29, 2016, 04:27

I'm working on thermal simulation for Car Lamp, it's include Thernmal Simulation, Sunloading, Condensation.
But in the last three months, we meet many divergence case in our work.
Now I'm focus to find some root issue on mesh quality, and our current mesh criterion is : 2D mesh skew <55, 3D mesh skew<0.9.
Wish some people give me some suggestion on this topic, is it has many more others attention points for meshing? and is it our criterion too low?
Thanks very much in advance for all your comment.

LuckyTran · April 29, 2016, 10:12

As long as you did everything else correctly, I would say mesh skewness is #1 or #2 suspect for divergence and slow convergence. Always try to reduce it. A skewness of 0.9-0.96 is acceptable, but can still cause convergence issues. Even 0.7 or 0.8 is a big help.

High aspect ratio cells lead to some inaccuracies in terms of discretization, but they generally do cause any problems. You can use cell aspect ratios of 100 or 200 if they are high quality cells.

April 29, 2016, 04:27	Topic: what's good mesh criterion for Fluent?	#1
liujiangkun New Member Jiangkun LIU Join Date: Apr 2016 Posts: 1 Rep Power: 0	I'm working on thermal simulation for Car Lamp, it's include Thernmal Simulation, Sunloading, Condensation. But in the last three months, we meet many divergence case in our work. Now I'm focus to find some root issue on mesh quality, and our current mesh criterion is : 2D mesh skew <55, 3D mesh skew<0.9. Wish some people give me some suggestion on this topic, is it has many more others attention points for meshing? and is it our criterion too low? Thanks very much in advance for all your comment. Last edited by liujiangkun; April 29, 2016 at 04:29. Reason: update

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April 29, 2016, 10:12		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,753 Rep Power: 66	As long as you did everything else correctly, I would say mesh skewness is #1 or #2 suspect for divergence and slow convergence. Always try to reduce it. A skewness of 0.9-0.96 is acceptable, but can still cause convergence issues. Even 0.7 or 0.8 is a big help. High aspect ratio cells lead to some inaccuracies in terms of discretization, but they generally do cause any problems. You can use cell aspect ratios of 100 or 200 if they are high quality cells.