[dogan]

Hi everybody,
I am working on the wall treatment in OpenFOAM, and as i've learned, the so called nutUSpaldingWallFunction is giving very good results in all y+ regions. I also made some calculations with it using kOmegaSST turbulence model, and as expected, it gave me very good results. But i would like to go deep with this wall treatment, and i would like to know the formulation (governing equations) of this wall function. Does anyone can help me with this? how can i find the governing equations of nutUSpaldingWallFunction in OpenFOAM?
thanks in advance
Dogan

[fumiya]

Hi dogan,

You might want to read the doctoral thesis by Dr. Eugene de Villiers(pp.80-81):

http://powerlab.fsb.hr/ped/kturbo/Op...ersPhD2006.pdf

Best regards,
Fumiya

[hz283]

Hi,

the source paper:

Spalding, a single formula for the law of the wall. Journal of applied mechanics. 1961.

The story is complete there.

Originally Posted by dogan

Hi everybody,
I am working on the wall treatment in OpenFOAM, and as i've learned, the so called nutUSpaldingWallFunction is giving very good results in all y+ regions. I also made some calculations with it using kOmegaSST turbulence model, and as expected, it gave me very good results. But i would like to go deep with this wall treatment, and i would like to know the formulation (governing equations) of this wall function. Does anyone can help me with this? how can i find the governing equations of nutUSpaldingWallFunction in OpenFOAM?
thanks in advance
Dogan

[dogan]

Thanks a lot to you all,
it really helped your answers.
regards
Dogan

[albet]

Hello Foamers,

I am solving the 3D flow around the cylindrical pile in OpenFOAM 2.3, as a single-phase with RANS (k-omegaSST) with simpleFoam.
I want to solve it with low-Re model near the bed.
my mesh is generated with ICEM and the yplus is less than 2 for all cells in bed. I have used the o-grid mesh around the cylinder.
the boundary that has been applied to the bed for turbulence properties are:

    BED
   nut
    {
        type            calculated;
        value           uniform 0;
    }
  omega
    { 
        type            omegaWallFunction;
        value           uniform 1000;

    }
   k
    {
        type            fixedValue;
        value           uniform 1e-10;
    }

and here is my fvSchemes

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;  
    grad(U)         cellLimited Gauss linear 1;
    grad(k)         cellLimited Gauss linear 1; 
    grad(omega)     cellLimited Gauss linear 1; 
}

divSchemes
{
    default         none;
    div(phi,U)      bounded Gauss linearUpwindV grad(U); 
    div(phi,k)      bounded Gauss upwind;
    div(phi,omega)  bounded Gauss upwind;
    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear limited 0.333;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         limited corrected 0.333;
}

fluxRequired
{
    default         no;
    p;
    Phi;
}

I have attached the results of the bed shear stress from wallShearStress utility. as you can see there is a problem in area generated with o-grid. changing the size of the mesh or resolution of the mesh do not change anything.

when I used the nutUSpaldingWallFunction for nut the results are very good.
I think the problem is the orthogonality of the cells in o-grid part!!
Could anybody help me with this problem?

Bests,
Amir