CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   Main CFD Forum (https://www.cfd-online.com/Forums/main/)
-   -   Y-plus calculation? (https://www.cfd-online.com/Forums/main/135141-y-plus-calculation.html)

basharf May 9, 2014 10:38

Y-plus calculation?
 
2 Attachment(s)
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?

Hamidzoka May 10, 2014 23:59

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.

basharf May 11, 2014 00:36

Quote:

Originally Posted by Hamidzoka (Post 491074)
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!

Hamidzoka May 12, 2014 02:04

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.

basharf May 12, 2014 02:45

Quote:

Originally Posted by Hamidzoka (Post 491167)
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


All times are GMT -4. The time now is 05:30.