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-   -   Rough baundary in atmospheric wind (http://www.cfd-online.com/Forums/openfoam-solving/58637-rough-baundary-atmospheric-wind.html)

majidhojjat August 18, 2008 09:51

Hi! I am modeling the wind
 
Hi!

I am modeling the wind effect on a cubic building. and first, to get the proper approaching flow (similar to experimental data) I am modeling an empty wind channel.
prescribing the inlet velocity, I produce the Ux profile. but for turbulence intensity (or k) using the inlet is not hopeful and I guess I should use a rough wall function to get the desired profile.

I tried using nutStandardRoughWallFunction but it was not really effective. even changing value of roughness length or... did not change anything.
To have a rough wall, is it enough just to add nutStandardRoughWallFunction as the physical type in boundary file and to specify roughness length and other parameters in /0/k ?

I am using OF 1.4.1 and I tried the mentioned problem in kEpsilon and kOmegaSSt as well as LES models.

Thanks!

eugene August 18, 2008 10:11

nut boundary conditions are on
 
nut boundary conditions are only effective in conjunction with the SpalartAllmaras model.

majidhojjat August 18, 2008 10:30

thank you for your answer, so
 
thank you for your answer,
so, there is no ready rough wall function to be used in other models?
and to maintain turbulence intensity profile I just have the choice of modifying the inlet values?

eugene August 18, 2008 11:15

For the other models the wall
 
For the other models the wall functions are hard-coded.

Not sure about the turbulence intensity profile.


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