# How does Star calculate "Cell Aspect Ratio" for Polyhedrals and Prism-Layers?

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 April 27, 2018, 10:22 How does Star calculate "Cell Aspect Ratio" for Polyhedrals and Prism-Layers? #1 New Member   Jonas Abeken Join Date: Apr 2018 Location: Zurich Posts: 10 Rep Power: 6 Hi, I'm having the issue, that I want to optimize my mesh regarding Aspect Ratio of the cells. Best practice for my case suggests to keep the Aspect Ratio below 50. Now, when I look at the available parameter "Cell Aspect Ratio" it gives me values between 0 and 1, with 1 being the best. However I wasn't able to figure out, how this value is actually calculated. With normalized Aspect Ratios, I'm used to something like Min(Distance between faces of cell)/Max(Distance between faces of cell), or the same but with distances from centroid to face-centroid. But simply measuring cells and recalculating this value by hand gives me completely different results than given by the field function "cell aspect ratio". Can someone tell me how Star calculates its "cell aspect ratio", so I can relate the suggested value of >50 to some value of this parameter? Any help is greatly appreciated! Thanks and best regards! Jonas Last edited by jabeken; April 27, 2018 at 10:23. Reason: clarification

May 23, 2022, 08:11
Have you found the reason???
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Quote:
 Originally Posted by jabeken Hi, I'm having the issue, that I want to optimize my mesh regarding Aspect Ratio of the cells. Best practice for my case suggests to keep the Aspect Ratio below 50. Now, when I look at the available parameter "Cell Aspect Ratio" it gives me values between 0 and 1, with 1 being the best. However I wasn't able to figure out, how this value is actually calculated. With normalized Aspect Ratios, I'm used to something like Min(Distance between faces of cell)/Max(Distance between faces of cell), or the same but with distances from centroid to face-centroid. But simply measuring cells and recalculating this value by hand gives me completely different results than given by the field function "cell aspect ratio". Can someone tell me how Star calculates its "cell aspect ratio", so I can relate the suggested value of >50 to some value of this parameter? Any help is greatly appreciated! Thanks and best regards! Jonas

Hi,
Does anybody know the reason or the equation behind this strange method?
I also faced the same problem.

Best,

 Tags aspect ratio, cell aspect ratio, mesh quality