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March 10, 2014, 09:37 |
spatial resolution in StarCCM+ for LES
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#1 |
Member
Aqua
Join Date: Oct 2011
Posts: 96
Rep Power: 14 |
Dear All, I am performing LES in StarCCM+. To make sure the mesh is reasonable, I need to check the spatial resolution including Y+, as well as X+ and Z+ in the other two directions. StarCCM+ already has the field function of Y+, but how to get the spacitial resolution for the other direction, X+ and Z+?
Thank you so so much ! Aqua |
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March 10, 2014, 11:20 |
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#2 |
Senior Member
Join Date: Nov 2010
Location: USA
Posts: 1,232
Rep Power: 24 |
Y+ does not refer to a specific direction, it is a parameter which is relative to the local face normal. X+ and Z+ do not exist.
Please read up here: http://en.wikipedia.org/wiki/Law_of_the_wall |
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March 10, 2014, 12:03 |
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#3 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,399
Rep Power: 46 |
and do exist.
You can estimate them through the extent of the cell in the respective direction. Say you have a certain value of for a cell which has an extent of in y-direction. Then the value for is . Same with . Pay attention that this concept is only valid for the first cell near a wall where is related to the wall-normal extent of the cell. |
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March 10, 2014, 12:20 |
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#4 |
Senior Member
Join Date: Nov 2010
Location: USA
Posts: 1,232
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I meant they don't exist in STAR-CCM+, sorry.
I don't see any method of calculating these values without user code, unless the geometry is simple enough to know the cell dimensions a priori. |
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March 11, 2014, 06:52 |
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#5 |
Member
Aqua
Join Date: Oct 2011
Posts: 96
Rep Power: 14 |
Hi, thank you very much for your reply... which really shocked me... StarCCM+ does not have x+ and z+ ? OMG... If that's true, I would have big trouble with my work..
Thank you. Aqua |
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March 11, 2014, 06:57 |
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#6 |
Member
Aqua
Join Date: Oct 2011
Posts: 96
Rep Power: 14 |
Hello Alex, thank you for your kind reply. I understand your explanation, but my problem is , how to get it from StarCCM+... do you have any idea?
In Starccm+, I can get Y+, but then , to calculate X+ and Z+, I would need the size of the cell (width or length), which is an issue for me... Thank you Aqua Quote:
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March 11, 2014, 10:29 |
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#7 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,399
Rep Power: 46 |
No need to be shocked, no general purpose commercial CFD software has predefined functions for these values.
As pointed out by me3840, you will need some user code to get them unless you have a very simple setup. I am no longer working with CCM+, so I cant really give you a hint how to do this. |
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