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-   -   boundaryWallFunctionsProfile Tutorial yPlus / wall functions (https://www.cfd-online.com/Forums/openfoam-solving/183623-boundarywallfunctionsprofile-tutorial-yplus-wall-functions.html)

RK_Token February 8, 2017 15:18

boundaryWallFunctionsProfile Tutorial yPlus / wall functions
 
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Hallo,


I‘m trying to understand the „boundaryWallFunctionsProfile“ tutorial, in the way how the wall functions are being handled by OpenFOAM for the different yPlus (y+) values.

As far as I have understand, if y+ <= 1 (or 5) no wall function is needed and for y+>= 30 wall functions have to be applied. Further more its not recommended to run simulations with y+ within the buffer-layer region (5 < y+ < 30).

So now if I check the output of the tutorial, we get proper u+ values for y+ values within all three regions, beside a wall-function (nutkWallFunction) was defined within the 0/nut file.

My assumption would be to get bad results for small y+.


So Is OpenFoam ignoring wall-functions if y+ is smaller than 30, or is some blending going on?


Thank you and best regards.


related topics.

https://www.cfd-online.com/Forums/op...penfoam-2.html

https://www.cfd-online.com/Forums/op...ion-usage.html

ari003 February 17, 2021 08:13

Quote:

Originally Posted by RK_Token (Post 636438)
Hallo,


I‘m trying to understand the „boundaryWallFunctionsProfile“ tutorial, in the way how the wall functions are being handled by OpenFOAM for the different yPlus (y+) values.

As far as I have understand, if y+ <= 1 (or 5) no wall function is needed and for y+>= 30 wall functions have to be applied. Further more its not recommended to run simulations with y+ within the buffer-layer region (5 < y+ < 30).

So now if I check the output of the tutorial, we get proper u+ values for y+ values within all three regions, beside a wall-function (nutkWallFunction) was defined within the 0/nut file.

My assumption would be to get bad results for small y+.


So Is OpenFoam ignoring wall-functions if y+ is smaller than 30, or is some blending going on?


Thank you and best regards.


related topics.

https://www.cfd-online.com/Forums/op...penfoam-2.html

https://www.cfd-online.com/Forums/op...ion-usage.html

Hello RK, I m not a profound user of Openfoam who can certainly help you with this issue. But was just curious if I can use this script to plot the y+ vs u+ graph for any other solver or not. If you have any idea could you please share how can I compile this with a pimpleFoam solver?


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