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Regarding Y+

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Old   November 18, 2009, 05:16
Thumbs up Regarding Y+
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stephenraj
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hi friend i have one doubt where i have to give the value of y + in starccm during simulation
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Old   November 18, 2009, 20:28
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Hey there,

As I understand it, you control your Y+ by the prism layer meshing settings.

There you can specify 1st wall thickness, total boundary layer thickness, number of cells etc.

These, as you know from your aerodynamics theory,then control your Y+.

If you want a more detailed explanation, let me know and I can supply you with the equations or links to them.

Hope this helps.

Last edited by aerospaceman; November 24, 2009 at 11:53.
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Old   December 9, 2009, 09:04
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madhu
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hi aerospaceman,

I am wondering how to figure out the boundary layer thickness for a nozzle flow.
Could you give me a detailed explanations, if possible with equations.
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Old   January 3, 2010, 01:36
Default How to control the y+ value in Star-CCM+ ?
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nguyen van trieu
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Quote:
Originally Posted by aerospaceman View Post
Hey there,

As I understand it, you control your Y+ by the prism layer meshing settings.

There you can specify 1st wall thickness, total boundary layer thickness, number of cells etc.

These, as you know from your aerodynamics theory,then control your Y+.

If you want a more detailed explanation, let me know and I can supply you with the equations or links to them.

Hope this helps.
Hello Aerospaceman,

I've been working with Star-CCM+ V3.06. I would like to know how to estimate the y+, as you said by using "prism layer mesher" right? so could you tell me more clearly?
thanks in advance!

email: trieuckgt@gmail.com
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YM: trieu_tme@yahoo.com
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Old   January 7, 2010, 09:24
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Hi

i'm not sure, if i've understood your problem the right way.
A good estimation for the near wall prism layer of a flat plate could be found by using the tool on http://geolab.larc.nasa.gov/APPS/YPlus/ .
I'm doing simulation on an airfoil, so i specify the near wall prism layer thickness, using the value calculated by this tool, and it works very well.

After the simulation, you should do a scalar plot of the y+ value and adjust the near wall prism layer thickness if the y+ does not meet the requirements.

greetings
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Old   February 21, 2010, 15:41
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Asherah
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Quote:
Originally Posted by abdul099 View Post
Hi

i'm not sure, if i've understood your problem the right way.
A good estimation for the near wall prism layer of a flat plate could be found by using the tool on http://geolab.larc.nasa.gov/APPS/YPlus/ .
I'm doing simulation on an airfoil, so i specify the near wall prism layer thickness, using the value calculated by this tool, and it works very well.

After the simulation, you should do a scalar plot of the y+ value and adjust the near wall prism layer thickness if the y+ does not meet the requirements.

greetings
Hiya thank you for sharing that calculator, in that calculator, there is a refrence length, and output, what are they?

Many thanks

Asherah
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Old   February 22, 2010, 03:02
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The output is the thickness of the first layer. For CCM you must calc it with the stretching factor and the numbers of layer.
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Old   February 13, 2015, 05:53
Smile Y+ Calculator
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Jan N. Wieczorek
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Hi Folks,
I don't know if you noticed, but CFD-Online has it's own Y+-Calculator!
It's very handy and gives you the near wall thickness as an ouput for your desired Y+-value.
It also gives a link to the wiki, where the formulas are explained in detail.
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