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wiedangel May 9, 2012 10:01

kOmegaSST OF2.1 Help needed!
 
3 Attachment(s)
Hi all,
I am trying to get a case of a flow over an airfoil to work using the turbulence model kOmegaSST. I have a mesh where yPlus is around 30. As it is stated in many papers and books this value shoulb be OK if one wants to use a wall function. I also read that the kOmegaSST in openFoam uses a wall function "by default" and one can not avoid using it (any comments on that?).

My parameters are attached to this thread, I donīt understand what I have done wrong, but when the Re number is 20.000 the case is working, but it will diverge when Re=700.000. Any help on this will be greatly appreciated as I am really lost with all what is written about kOmegaSST, as it seems that there are "many ways" to use it in OpenFoam.
I would like that this exchange space will serve to discuss that issue about kOmegaSST.
k:

Code:

internalField  uniform 0.06;

boundaryField
{
    inflow
    {
        type            fixedValue;
        value          uniform 0.06;
    }
    outflow
    {
        type            zeroGradient;
internalField  uniform 0.06;

boundaryField
{
    inflow
    {
        type            fixedValue;
        value          uniform 0.06;
    }
    outflow
    {
        type            zeroGradient;

omega:
Code:

internalField  uniform 0.00813;

boundaryField
{
    inflow
    { type            fixedValue;
        value          uniform 0.00813;
    }
    outflow
    {
        type            zeroGradient;
    }
    airfoil
    {
        type            omegaWallFunction;
        Cmu            0.09;
        kappa          0.41;
        E              9.8;
        beta1          0.075;
        value          uniform 0.00813;
    }
    frontAndBack
    {
        type            empty;
    }
}

nut
Code:

internalField  uniform 0;

boundaryField
{
    inflow
    {
        type            calculated;
        value          uniform 0;
    }
    outflow
    {
        type            calculated;
        value          uniform 0;
    }
    airfoil
    {
        type            nutWallFunction;
        Cmu            0.09;
        kappa          0.41;
        E              9.8;
        value          uniform 0;
    }
    frontAndBack
    {
        type            empty;
    }
}

I also attached some pics of the mesh I am using.


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