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-   -   yPlusRAS in pisoFOAM (https://www.cfd-online.com/Forums/openfoam/90238-yplusras-pisofoam.html)

Akuji July 5, 2011 07:25

yPlusRAS in pisoFOAM
 
Hello!

I had some troubles with calculating yplus. Well, I use OF-1.7.1, model is Spalart-Allmaras. In terminal after calculating pisoFoam I type yPlusRAS and for all my time steps I have the same result:


Reading field U
Reading/calculating face flux field phi
Selecting incompressible transport model Newtonian
Selecting RAS turbulence model SpalartAllmaras
SpalartAllmarasCoeffs
{
sigmaNut 0.66666;
kappa 0.41;
Cb1 0.1355;
Cb2 0.622;
Cw2 0.3;
Cw3 2;
Cv1 7.1;
Cv2 5;
}

Patch 3 named ground y+ : min: 0 max: 0 average: 0
Patch 6 named nok y+ : min: 0 max: 0 average: 0
Writing yPlus to field yPlus

Why I have this result?

Eren10 July 5, 2011 09:19

did you specified any wall ?

Akuji July 5, 2011 09:26

Quote:

Originally Posted by Eren10 (Post 314768)
did you specified any wall ?

yes. As I understand, terminal saw my patches [walls]
Patch 3 named ground y+ : min: 0 max: 0 average: 0
Patch 6 named nok y+ : min: 0 max: 0 average: 0

Akuji July 8, 2011 04:26

Or maybe I should create a yPlusRAS file in folder 0 by myself?

Eren10 July 8, 2011 06:05

Quote:

Originally Posted by Akuji (Post 315274)
Or maybe I should create a yPlusRAS file in folder 0 by myself?


which files do you have at constant directory ?

I am using Kepsilon, and I just type yPlusRAS and it works.

Akuji July 8, 2011 07:17

Quote:

Originally Posted by Eren10 (Post 315297)
which files do you have at constant directory ?

In every directory I have files:
cellToRegion
nut
nuTilda
p
U
y
yPlus

(I use Spalart-Allmaras model).
In y file I saw a lot of numbers, but yPlus is similar to file nut (in structure)

Eren10 July 8, 2011 07:53

you dont need that files in every directory. at constant/ directory you should have transportProperties RASproperties .. and some of these kind files, check tutorials

Akuji July 8, 2011 07:57

Quote:

Originally Posted by Eren10 (Post 315329)
you dont need that files in every directory. at constant/ directory you should have transportProperties RASproperties .. and some of these kind files, check tutorials

I don't understand you first time. In /constant directory I ' ve got 3 files: RASPropeties, transportPropeties and turbulencePropeties. They are ok.
I may to attach them.

Eren10 July 8, 2011 08:24

You can check if yPlusRAS works on a tutorial that runs a turbulence model, try k-epsilon. and than compare your case with that, sorry I am also just a "user"

flowris August 31, 2011 05:15

y+ without wall function
 
I have done simulations with kOmega SST and a wall function, and was able to calculate y+ using the command yPlusRAS.

However, now I want to do similar things, WITHOUT the wall function and integrating through the boundary layers. When I run yPlusRAS after the simulation, I get the message that I do not have a wall patch. I change this in the constant/polyMesh/boundary and I run the command again. Result: y-field can be calculated correctly, but there is still the complaint
Code:

    no nutWallFunction patches
Writing yPlus to field yPlus

What can I do? I don't have a nut wall function, but do I also have to change this in every time step after the simulation?


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