[Petr Kazarin]

Hello colleagues,

I am modeling the fanwing in Openfoam (the fan embedded in between slat and airfoil).
I am using cyclicAMI etc - it works. The fan rotates with 400 rad/s and I get the transient solution.
However, the lift coefficient on slat and airfoil oscillates too much - almost from 1 to 10.. I calculated the mean value over time history and got smthg like 4.5 which is somewhat close to the value I got from Fluent. In fluent there are no such oscillations - the lift coefficient grows gradually up to 5.2-5.3 with very small oscillations.
I use SpalartAllmaras model. The freestreeam value is 15 m/s,

The fVSchemes I use is as follows:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.1                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         Euler;
}

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

divSchemes
{
    default         none;
//    div(phi,U)      Gauss upwind;
    div(phi,U)      Gauss limitedLinear 1;//Gauss linearUpwind grad(U);//Gauss linearUpwind grad(U);
   // div(phi,k)      Gauss linear;//Gauss upwind;
   // div(phi,omega) Gauss linear;//Gauss upwind;
    div((nuEff*dev2(T(grad(U))))) Gauss linear;
    
    div(phi,nuTilda)  bounded Gauss linearUpwind grad(nuTilda);
}

laplacianSchemes
{
    default         Gauss linear limited corrected 0.33;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         limited corrected 0.33;
}
wallDist
{
method meshWave;
}


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

fvSolutions is:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.1                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    pcorr
    {
        solver          GAMG;
      //  preconditioner  DIC;
        tolerance       1e-2;
        relTol          0;
        smoother        DICGaussSeidel;
        cacheAgglomeration no;
        maxIter         200;
    }

    p
    {
        $pcorr;
        tolerance       1e-5;
        relTol          0.01;
    }

    Phi
    {
        $p;
    }

    pFinal
    {
        $p;
        tolerance       1e-6;
        relTol          0;
    }

    "(U|nuTilda)"
    {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        //solver          PBiCGStab;
      //  preconditioner  DILU;
        tolerance       1e-6;
        relTol          0.1;
    }

    "(U|nuTilda)Final"
    {
        solver          smoothSolver;
       smoother        symGaussSeidel;
      // solver          PBiCGStab;
    //    preconditioner  DILU;
        tolerance       1e-6;
        relTol          0;
    }
}

potentialFlow
{
    nNonOrthogonalCorrectors 10;
    PhiRefCell 0; 
    PhiRefValue 0; 
}

SIMPLE
{
nCorrectors     2;    
nNonOrthogonalCorrectors 0;
     
    consistent yes;
}



PIMPLE
{
    correctPhi          no;
    nOuterCorrectors    3;
    nCorrectors         1;
    nNonOrthogonalCorrectors 1;
}

relaxationFactors
{
    U       0.5;
    UFinal  1;
}

cache
{
    grad(U);
}

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

I noticed that Residual for pressure is very high (up to 1).
Could you please give some advise of hot to suppress the residual for p ?