[tareqkh]

Hello people,

I have been trying to use the kOmegaSST model implemented in OF 2.3.3, to simulate backward facing step. I have created three grids in order to do grid convergence study properly. However, I am a little bit confused about sitting boundary conditions for both k and omega properly. For instance, k and omega for examples in simpleFoam have been set up using wall function, and my feeling is that wall function does not work with y+=1 since it will not be resolving the boundary layer. I really would appreciate your help in this regard.

Following are the boundary conditions for my turbulent parameters :

k

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0.015;

boundaryField
{
    front
    {
        type            slip;
    }
    inlet
    {
        type            fixedValue;
        value           uniform 0.015;
    }
    top
    {
        type            fixedValue;//kqRWallFunction;
        value           uniform 1e-10;//0.015;
    }
    bottom
    {
        type            fixedValue;//kqRWallFunction;
        value           uniform 1e-10;//0.015;
    }
    back
    {
        type            slip;
    }
    outlet
    {
        type            zeroGradient;
    }
}


// ************************************************************************* //

omega

| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 -1 0 0 0 0];

internalField   uniform 4.1744;

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform 4.1744;
    }
    outlet
    {
        type            zeroGradient;
    }
    top
    {
        type            fixedValue;//omegaWallFunction;
        value           uniform 1e+10;//4.1744;
    }
    bottom
    {
        type            fixedValue;//omegaWallFunction;
        value           uniform 1e+10;//4.1744;
    }
    front
    {
        type            slip;
    }
    back
    {
        type            slip;
    }
}


// ************************************************************************* //

p

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    inlet
    {
        type            zeroGradient;
    }

    outlet
    {
        type            fixedValue;
        value           uniform 0;
    }

    top
    {
        type            zeroGradient;
    }

    bottom
    {
        type            zeroGradient;
    }

    front
    {
        type            slip;
    }

    back
    {
        type            slip;
    }

}

// ************************************************************************* //

U

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform (1 0 0);
    }

    outlet
    {
        type            zeroGradient;
    }

    top
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    bottom
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    front
    {
        type            slip;
    }
    back
    {
        type            slip;
    }
}

// ************************************************************************* //