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March 7, 2013, 12:34 |
y+ values calculation in OpenFoam
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#1 |
Member
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14 |
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 |
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March 8, 2013, 04:13 |
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#2 |
Senior Member
Sasan Ghomi
Join Date: Sep 2012
Location: Denmark
Posts: 292
Rep Power: 15 |
If your problem is caculation of y+ , So you can use :
yPlusRAS -----> incompressible flow yPlusRAS -compressible ---------> compressible flow Sasan. |
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March 8, 2013, 04:23 |
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#3 |
Member
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14 |
Ok then.
I run yPlusRans but i get a min value a max value and an average value... what does mean? |
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March 8, 2013, 06:27 |
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#4 |
Senior Member
Join Date: Aug 2010
Location: Groningen, The Netherlands
Posts: 216
Rep Power: 19 |
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 |
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March 8, 2013, 06:39 |
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#5 |
Member
AndreiCFD
Join Date: Nov 2012
Posts: 47
Rep Power: 14 |
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 |
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