|
[Sponsors] |
August 10, 2012, 13:23 |
How to decide Y plus
|
#1 |
New Member
prashant kadam
Join Date: Dec 2009
Location: Pune
Posts: 19
Rep Power: 16 |
Hello All,
I have question how to decide the y plus?
__________________
regards, Prashant |
|
August 10, 2012, 13:50 |
|
#2 |
Administrator
Peter Jones
Join Date: Jan 2009
Posts: 682
Rep Power: 10 |
You should check CFD-Wiki and the online tools we have here at CFD Online:
Here is a tool to compute the needed wall distance for a desired y-plus: http://www.cfd-online.com/Tools/yplus.php Here are the formulas used: http://www.cfd-online.com/Wiki/Y_plu...nce_estimation Here is the definition of y plus: http://www.cfd-online.com/Wiki/Dimen...e_%28y_plus%29 |
|
August 12, 2012, 02:52 |
|
#3 |
New Member
prashant kadam
Join Date: Dec 2009
Location: Pune
Posts: 19
Rep Power: 16 |
Thanks for your reply,
I have done the calculations by using the formulas which you have suggested. But I don't know how to choose the y plus for the calculation of the first cell height. My mass flow is 0.055 m/s for air. By calculation i got Re=52401, Rho=1.18415, but when I take the y plus value 80 then the first cell height is 4.37 mm.. But wb=hen i take y plus = 1 then first cell height is 0.055 mm. is that correct. One more question, On which basis we can select the y plus value for the calculation of the first cell height. As per my study y plus between 1-3 is viscous sub-layer or laminar region , 3-30 transition layer, and 30-120 or 150 is turbulent layer. but on which basis should i choose the y plus value. when Reynolds no is more boundary layer is small. then the region is viscous sub-lyer near the wall.
__________________
regards, Prashant |
|
August 12, 2012, 03:29 |
|
#4 |
Administrator
Peter Jones
Join Date: Jan 2009
Posts: 682
Rep Power: 10 |
What y plus you want depends on what turbulence model you use.
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
How to decide time step size | caohan | FLUENT | 3 | September 8, 2010 03:30 |
How to decide the mesh size? | echo | Siemens | 1 | May 23, 2006 05:34 |
how to decide the shroud and hub line | angel | Fidelity CFD | 4 | April 1, 2003 02:39 |
how to decide free boundary condition | laofan | Main CFD Forum | 9 | January 4, 2001 03:07 |
how to decide coefficient of k-w modeling | Lee, Juhee | Main CFD Forum | 4 | May 6, 1999 01:52 |