[Clmkite]

Hi everyone,

I'm trying to determine performances of an axial fan.
Profil naca4412 and 36 blades.
First, I tried with the solver SRFSimpleFoam but my results seemed to be innacurate.
So I want to try with multiple frame with simpleFoam and FvOptions and it wil be a good training also because I strat OpenFoam recenttly.

My mesh is 10deg sectors with one blade ond cyclicAMI boundaries.
Inlet : 10m.s-1
rot : 900RPM

My problem is that my time step continuity errors go very high (e+90) !

You can fin the whole case here

Link to case : folders and mesh

and here there is boundarys, fvschemes, u and p fields;

FoamFile
{
    version     2.0;
    format      ascii;
    class       polyBoundaryMesh;
    location    "constant/polyMesh";
    object      boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

10
(
    inlet
    {
        type            patch;
        nFaces          78;
        startFace       5460135;
    }
    outlet
    {
        type            patch;
        nFaces          70;
        startFace       5460213;
    }
    outerwall
    {
        type            wall;
        inGroups        1(wall);
        nFaces          146;
        startFace       5460283;
    }
    cycl1stat
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          6286;
        startFace       5460429;
        transform       rotational;
        neighbourPatch  cycl2stat;
        rotationAxis    (0 0 1);
        rotationCentre  (0 0 0);
    }
    cycl2stat
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          6286;
        startFace       5466715;
        transform       rotational;
        neighbourPatch  cycl1stat;
        rotationAxis    (0 0 1);
        rotationCentre  (0 0 0);
    }
    cycl1rot
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          7417;
        startFace       5473001;
        transform       rotational;
        neighbourPatch  cycl2rot;
        rotationAxis    (0 0 1);
        rotationCentre  (0 0 0);
    }
    cycl2rot
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          7417;
        startFace       5480418;
        transform       rotational;
        neighbourPatch  cycl1rot;
        rotationAxis    (0 0 1);
        rotationCentre  (0 0 0);
    }
    innerwallrot
    {
        type            wall;
        inGroups        1(wall);
        nFaces          150;
        startFace       5487835;
    }
    innerwallstat
    {
        type            wall;
        inGroups        1(wall);
        nFaces          446;
        startFace       5487985;
    }
    blade
    {
        type            wall;
        inGroups        1(wall);
        nFaces          89034;
        startFace       5488431;
    }
)

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            uniformFixedValue;
        uniformValue    0;
    }
    outerwall
    {
        type            zeroGradient;
    }
    innerwallrot
    {
        type            zeroGradient;
    }
    innerwallstat
    {
        type            zeroGradient;
    }
    blade
    {
        type            zeroGradient;
    }
    cycl1stat
    {
        type            cyclicAMI;
    }
    cycl2stat
    {
        type            cyclicAMI;
    }
    cycl1rot
    {
        type            cyclicAMI;
    }
    cycl2rot
    {
        type            cyclicAMI;
    }
}

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 (0 0 10);
    }
    outlet
    {
        type            inletOutlet;
        value           $internalField;
        inletValue      uniform (0 0 0);
    }
    outerwall
    {
        type            slip;
    }
    innerwallrot
    {
        type            slip;
    }
    innerwallstat
    {
        type            slip;
    }
    blade
    {
        type            fixedValue;
        value           uniform ( 0 0 0 );
    }
    cycl1stat
    {
        type            cyclicAMI;
    }
    cycl2stat
    {
        type            cyclicAMI;
    }
    cycl1rot
    {
        type            cyclicAMI;
    }
    cycl2rot
    {
        type            cyclicAMI;
    }
}

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      bounded Gauss limitedLinearV 1;
    div(phi,k)      bounded Gauss limitedLinear 1;
    div(phi,epsilon) bounded Gauss limitedLinear 1;
    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p               ;
}

Also, if you have have any recommandations I'd be glad to hear it.

Thanks a lot

[maHein]

Hello,

cyclicAMI should be specified as "nonRotatingPatches" in fvOptions:

MRF1
{
    type            MRFSource;
    active          true;
    selectionMode   cellZone;
    cellZone        rotor;

    MRFSourceCoeffs
    {
        active      true;
        origin      (0 0 0);
        axis        (0 0 1);
        omega       -90;

        nonRotatingPatches
        (
            cycl1stat
            cycl2stat
            cycl1rot
            cycl2rot
        );
    }
}

It should work then.

Kind regards,

Martin

[Clmkite]

Hi Martin,

Thanks a lot for your answers.
You solved this porblems.

I still have some convergence problems but for now I'm trying to solve them by myself.

Regards,
Clement