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-   -   yPlusRAS : result = 0 (https://www.cfd-online.com/Forums/openfoam-solving/69190-yplusras-result-0-a.html)

jmf October 14, 2009 15:43
yPlusRAS : result = 0
 
Hello dear all

Situation of a novice : I fail in using yPlusRAS
After running simpleFoam, yPLusRAS returns following message :
"Patch 0 named wall y+ : min: 0 max: 0 average: 0"

It creates a yPLus containing :
Code:
internalField  uniform 0;
boundaryField
{
    wall
    {
        type            calculated;
        value          uniform 0;
    }
    inlet
    {
        type            calculated;
        value          uniform 0;
    }
    outlet
    {
        type            calculated;
        value          uniform 0;
    }
and a file 'y' with non null values (almost one value per model node), of which the average is 0.38

What did I miss ?

Best regards

Jean-Michel

lakeat October 15, 2009 05:34
Since yPlus is calculated by
Code:
    if (isType<wallFvPatch>(curPatch))
    {
        Yp = pow(Cmu, 0.25)
            *y_[patchNo]
            *sqrt(k()().boundaryField()[patchNo].patchInternalField())
            /nu().boundaryField()[patchNo];
    }
in file RASModel.C

So, I am bold to guess something wrong with the k field, eg. you are missing it?

jmf October 15, 2009 16:16
yPlusRAS : result = 0
 
Hi Daniel

My k dictionary contains:
Code:
inlet
    {
        type            fixedValue;
        value          uniform 3 ;
    }
    outlet
    {
        type            zeroGradient;
    }
    wall
    {
        type            kqRWallFunction;
        value          uniform 5;
    }
and Cmu = 0.09

Is following message from solver normal :
"smoothSolver: Solving for nuTilda, Initial residual = 0, Final residual = 0, No Iterations 0" ?

Thanks for your help
J-Michel

tian October 16, 2009 03:36
Hi,

maybe you have to set the boundary patch to "wall"?

Byt
Thomas

jmf October 17, 2009 06:02
yPlusRAS : result = 0
 
Hi Thomas

The boundary patches are set to "wall"

Thanks to everybody for the time

J-Michel


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