Wall threatment

webceo89 · January 13, 2011, 07:56

Hello,

I am modelling a windtunnel in order to receive a drag coefficient for a vehicle.

The vehicle I use has a Reynolds number of 4,29 million. I am using the k-omega turbulence model.

How do I know, if my y+ values have to be smaller than 1 oder bigger than 30?

I am using SC-Tetra and the results of the calculations give me the following range of values for y+:

(YPLUS DISTRIBUTION)
0.0 - 1.0 : 31
1.0 - 2.0 : 45
2.0 - 5.0 : 279
5.0 - 11.6 : 813
11.6 - 1000.0 : 17863
1000.0 - Inf : 0

I used 5 prism layer with a growing rate of 1.3.
The first prism layer has a size of 1E-3 m.

Can somebody tell me how to get the wall distance and which range to use?

Thank you.

Best regards

webceo89

mohammad · January 13, 2011, 23:47

[QUOTE=webceo89;290276]Hello,

I am modelling a windtunnel in order to receive a drag coefficient for a vehicle.

The vehicle I use has a Reynolds number of 4,29 million. I am using the k-omega turbulence model.

How do I know, if my y+ values have to be smaller than 1 oder bigger than 30?

I am using SC-Tetra and the results of the calculations give me the following range of values for y+:

(YPLUS DISTRIBUTION)
0.0 - 1.0 : 31
1.0 - 2.0 : 45
2.0 - 5.0 : 279
5.0 - 11.6 : 813
11.6 - 1000.0 : 17863
1000.0 - Inf : 0

I used 5 prism layer with a growing rate of 1.3.
The first prism layer has a size of 1E-3 m.

Can somebody tell me how to get the wall distance and which range to use?

-----------------------------------------------------------------------

Hi Webceo89

I had some problem with Y+. I don't know about SC-Tetra, but some thing i came into was that you must pay attention to the values of Yplus. they have a big influence on your run and even on your results.
plus read the following post
http://www.cfd-online.com/Forums/mai...e-y-yplus.html

it will help you.

January 13, 2011, 07:56	Wall threatment	#1
webceo89 New Member Join Date: Jan 2011 Posts: 3 Rep Power: 15	Hello, I am modelling a windtunnel in order to receive a drag coefficient for a vehicle. The vehicle I use has a Reynolds number of 4,29 million. I am using the k-omega turbulence model. How do I know, if my y+ values have to be smaller than 1 oder bigger than 30? I am using SC-Tetra and the results of the calculations give me the following range of values for y+: (YPLUS DISTRIBUTION) 0.0 - 1.0 : 31 1.0 - 2.0 : 45 2.0 - 5.0 : 279 5.0 - 11.6 : 813 11.6 - 1000.0 : 17863 1000.0 - Inf : 0 I used 5 prism layer with a growing rate of 1.3. The first prism layer has a size of 1E-3 m. Can somebody tell me how to get the wall distance and which range to use? Thank you. Best regards webceo89

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January 13, 2011, 23:47		#2
mohammad Senior Member mohammad Join Date: Dec 2010 Location: UK Posts: 245 Rep Power: 16	[QUOTE=webceo89;290276]Hello, I am modelling a windtunnel in order to receive a drag coefficient for a vehicle. The vehicle I use has a Reynolds number of 4,29 million. I am using the k-omega turbulence model. How do I know, if my y+ values have to be smaller than 1 oder bigger than 30? I am using SC-Tetra and the results of the calculations give me the following range of values for y+: (YPLUS DISTRIBUTION) 0.0 - 1.0 : 31 1.0 - 2.0 : 45 2.0 - 5.0 : 279 5.0 - 11.6 : 813 11.6 - 1000.0 : 17863 1000.0 - Inf : 0 I used 5 prism layer with a growing rate of 1.3. The first prism layer has a size of 1E-3 m. Can somebody tell me how to get the wall distance and which range to use? ----------------------------------------------------------------------- Hi Webceo89 I had some problem with Y+. I don't know about SC-Tetra, but some thing i came into was that you must pay attention to the values of Yplus. they have a big influence on your run and even on your results. plus read the following post http://www.cfd-online.com/Forums/mai...e-y-yplus.html it will help you.