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Y-plus calculation?

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Old   May 9, 2014, 11:38
Default Y-plus calculation?
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bashar
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Hello,

I am trying to calculate y plus for a drafttube as on picture. I understood that Y plus will be only calculate to the wall (boundary condition) of the domain. I calculated on post-CFD after I wrote the definition:

ave(Yplus)@ Diffuser Default

''Diffusor Default'' it is the wall of the draft tube.

Do you think that I am cacluated in the right way or? shall i write in this way:

areaAve(Yplus)@ Diffuser Default
Do you have any idea how to make a chart of Y-plus through all the drafttube?

I make a counter and use counter to show y- plus through all the draft tube, I attached picture on it. I used ''K-epsilon models'' . It seems that Yplus is very low in the counter so I wonder if I am doing right?
Attached Images
File Type: jpg test1.jpg (71.1 KB, 19 views)
File Type: jpg streamline_armbage_yplus.jpg (67.3 KB, 27 views)
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Old   May 11, 2014, 00:59
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Hamid Zoka
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Why do you need to make an averaged value for Yplus?
what is it good for?
As far as I know, A distribution (contour) of Yplus is needed to judge the quality of mesh near the solid walls.
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Old   May 11, 2014, 01:36
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Quote:
Originally Posted by Hamidzoka View Post
Why do you need to make an averaged value for Yplus?
what is it good for?
As far as I know, A distribution (contour) of Yplus is needed to judge the quality of mesh near the solid walls.
Thank you for your replay, I don't know what is he different between them. I used the average and it gave me 54. It seems good because the result must be as I read between 30 and 100. When I used contour to visualise the y-plus. It showed very low. You have a picture for counter attach in my equation. If you can check it and give your opinion about that!
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Old   May 12, 2014, 03:04
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The average value of Yplus is not helpful at all!
As I see the attached contour, there are regions with the Yplus of more than 200. It means that you need to select lower thickness for wall-adjacent cells at these regions.
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Old   May 12, 2014, 03:45
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Quote:
Originally Posted by Hamidzoka View Post
The average value of Yplus is not helpful at all!
As I see the attached contour, there are regions with the Yplus of more than 200. It means that you need to select lower thickness for wall-adjacent cells at these regions.
Thank you for your replay, I will check it. Do you know if there is possible to draw chart of the Y-plus value? If you have link so will be more easy to understand the process
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