# y+ values calculation in OpenFoam

 Register Blogs Members List Search Today's Posts Mark Forums Read

 March 7, 2013, 12:34 y+ values calculation in OpenFoam #1 New Member   AndreiCFD Join Date: Nov 2012 Posts: 27 Rep Power: 4 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

 March 8, 2013, 04:13 #2 Senior Member   Sasan Ghomi Join Date: Sep 2012 Location: Iran - Tehran Posts: 185 Rep Power: 4 If your problem is caculation of y+ , So you can use : yPlusRAS -----> incompressible flow yPlusRAS -compressible ---------> compressible flow Sasan.

 March 8, 2013, 04:23 #3 New Member   AndreiCFD Join Date: Nov 2012 Posts: 27 Rep Power: 4 Ok then. I run yPlusRans but i get a min value a max value and an average value... what does mean?

 March 8, 2013, 06:27 #4 Senior Member   Join Date: Aug 2010 Location: Groningen, The Netherlands Posts: 216 Rep Power: 9 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.

 March 8, 2013, 06:39 #5 New Member   AndreiCFD Join Date: Nov 2012 Posts: 27 Rep Power: 4 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

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Santos-Dumont FLUENT 1 May 1, 2011 21:15 chiven OpenFOAM Running, Solving & CFD 4 September 14, 2009 04:44 hjasak OpenFOAM 0 August 8, 2008 05:33 jussi OpenFOAM Installation 0 April 24, 2008 14:25 AB CD-adapco 6 November 15, 2004 05:41

All times are GMT -4. The time now is 01:40.