CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

y+ values calculation in OpenFoam

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By colinB

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 7, 2013, 12:34
Exclamation y+ values calculation in OpenFoam
  #1
Member
 
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14
andrei.cimpoeru is on a distinguished road
Is it anyone familiar with the calculation of the y+ value as well as the turbulent KE and turbulent omega?

I am have an airfoil and I am using Komega SST with simpleFoam with wall functions and when I look at my residuals my pressure doesn't drop and I am ending up with high residuals.

I am interested to drop my residuals below 10^(-4).......

Any ideas

Many thanks

Andrei
andrei.cimpoeru is offline   Reply With Quote

Old   March 8, 2013, 04:13
Default
  #2
Senior Member
 
Sasan Ghomi
Join Date: Sep 2012
Location: Denmark
Posts: 292
Rep Power: 15
sasanghomi is on a distinguished road
If your problem is caculation of y+ , So you can use :
yPlusRAS -----> incompressible flow
yPlusRAS -compressible ---------> compressible flow

Sasan.
sasanghomi is offline   Reply With Quote

Old   March 8, 2013, 04:23
Default
  #3
Member
 
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14
andrei.cimpoeru is on a distinguished road
Ok then.

I run yPlusRans but i get a min value a max value and an average value... what does mean?
andrei.cimpoeru is offline   Reply With Quote

Old   March 8, 2013, 06:27
Default
  #4
Senior Member
 
Join Date: Aug 2010
Location: Groningen, The Netherlands
Posts: 216
Rep Power: 19
colinB is on a distinguished road
Hey there,

i guess you are referring to yPlusRAS when you wrote yPlusRans?

However to answer your question:

y+ value is a dimensionless height of the first cell on a surface.
But when this cell hight is varying over the surface you get different values.

Since providing the cell heights of all cells is quite a lot information
as a rough indication only the smallest the highest and the average of
all cell heights are given.

Usually the max value is the most crucial one since you can see with this
one whether the values exceed the maximum allowable for using
wall functions.

I hope this helps
regards
Colin
Alhasan likes this.
colinB is offline   Reply With Quote

Old   March 8, 2013, 06:39
Default
  #5
Member
 
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14
andrei.cimpoeru is on a distinguished road
so for a High Re I should have a yplus around 30 when using wall functions
therefore I should keep an eye just on the max value of the yplus when running yPlusRas....
Collin correct me plz if I am wrong.
Thanks
andrei.cimpoeru is offline   Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Incoherent values of Cl in 2D calculation Santos-Dumont FLUENT 1 May 1, 2011 22:15
The calculation efficiency of OpenFOAM chiven OpenFOAM Running, Solving & CFD 4 September 14, 2009 05:44
OpenFOAM Training in Europe and USA hjasak OpenFOAM 0 August 8, 2008 06:33
Adventure of fisrst openfoam installation on Ubuntu 710 jussi OpenFOAM Installation 0 April 24, 2008 15:25
Warning 097- AB Siemens 6 November 15, 2004 05:41


All times are GMT -4. The time now is 22:43.