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Water pump setup OF4.1

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Old   December 13, 2018, 09:47
Default Water pump setup OF4.1
  #1
jcw
New Member
 
Christian Wolf
Join Date: Mar 2009
Posts: 24
Rep Power: 12
jcw is on a distinguished road
Hello!

(0) I am running into problems, simulating a water pump in simpleFoam and MRF approach. My goals is: After finishing the steady-state run, to continue transient run with pimpleDyMFoam with rigid body motion of rotor. At the moment, I do not get a reasonable result with simpleFoam.

(1) My approach:
(1a) The rotor is meshed with ICEM/Hexa. A periodic segment is copy and pasted in order to get a 360deg rotor mesh. Even meshing with Hexa, the mesh quality is not very good, as the blades have strong curvature.
(1b) The volute and outlet piping is meshed with StarCCM+ Trimmed cells.
(1c) The water inlet piping consists out of 2 pipings. Both are meshed in ICEM/Hexa. The interface between both piping is vertex conformal.
(1d) I use cyclicAMI interface for connection at inlet piping/rotor and rotor/volute.


(2) Settings:
(2a) To connect the vertex conformal meshes of (1c), I used

Code:
stitchMesh -perfect Interface-14 Interface-15
A new time directory called '1' is generated, including: (a) Inlet piping, (b) Rotor, (c) Volute and outlet piping.

(2b) cellZone_1 represents rotor mesh.

(3) CheckMesh shows:
Code:
checkMesh -time 1 -allTopology


Create time
 
Create polyMesh for time = 1

Enabling all (cell, face, edge, point) topology checks.

Time = 1

Mesh stats
    points:           4304866
    faces:            12601483
    internal faces:   12269440
    cells:            4143883
    faces per cell:   6.00184
    boundary patches: 17
    point zones:      0
    face zones:       1
    cell zones:       4

Overall number of cells of each type:
    hexahedra:     3960110
    prisms:        97026
    wedges:        7534
    pyramids:      152
    tet wedges:    21
    tetrahedra:    11036
    polyhedra:     68004
    Breakdown of polyhedra by number of faces:
        faces   number of cells
            4   7
            5   166
            6   8899
            7   36734
            8   4987
            9   9555
           10   624
           11   129
           12   4431
           13   119
           14   26
           15   2314
           16   13

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
  <<Found 18 neighbouring cells with multiple inbetween faces.
    Upper triangular ordering OK.
  <<Writing 36 unordered faces to set upperTriangularFace
    Face vertices OK.
    Topological cell zip-up check OK.
  <<Number of duplicate (not baffle) faces found: 9. This might indicate a problem.
  <<Number of faces with non-consecutive shared points: 27. This might indicate a problem.
  <<Writing 54 faces with non-standard edge connectivity to set edgeFaces
   *Number of regions: 3
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "1/cellToRegion"
  <<Writing region 0 (fully disconnected) with 3290580 cells to cellSet region0
  <<Writing region 1 (fully disconnected) with 108360 cells to cellSet region1
  <<Writing region 2 (fully disconnected) with 744943 cells to cellSet region2

Checking patch topology for multiply connected surfaces...
                   Patch    Faces   Points                  Surface topology
         IF-ROTOR-STATOR    25560    25920  ok (non-closed singly connected)
                     HUB    35100    36061  ok (non-closed singly connected)
             BLADE-FRONT     7110     7824  ok (non-closed singly connected)
                   BLADE    54870    56160  ok (non-closed singly connected)
                  SHROUD    51660    52020  ok (non-closed singly connected)
                IF-BC-IN    29880    30061  ok (non-closed singly connected)
                     TIP     6300     6816  ok (non-closed singly connected)
            Interface-14        0        0                        ok (empty)
    EXTRUSION-inlet-layer       60      120  ok (non-closed singly connected)
       FLUID-INLET-LAYER      765      796  ok (non-closed singly connected)
            Interface-15        0        0                        ok (empty)
                 TRM_SRF     5580     5640  ok (non-closed singly connected)
               EXTRUSION     2340     2400  ok (non-closed singly connected)
               IF-U-PUMP     1185     1216  ok (non-closed singly connected)
                    Wall    97902    89775  ok (non-closed singly connected)
    Volute_Mixing_Interface    12410    13142  ok (non-closed singly connected)
                  Outlet     1321     1401  ok (non-closed singly connected)

Checking geometry...
    Overall domain bounding box (-0.667384 -0.526093 -2.77437) (0.622538 0.540912 -2.17567)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-7.86524e-17 -9.76514e-17 5.06224e-17) OK.
    Max cell openness = 8.43072e-16 OK.
    Max aspect ratio = 21.7438 OK.
    Minimum face area = 1.5237e-09. Maximum face area = 0.000165698.  Face area magnitudes OK.
    Min volume = 3.0602e-13. Max volume = 1.33109e-06.  Total volume = 0.0405201.  Cell volumes OK.
    Mesh non-orthogonality Max: 84.4003 average: 37.6213
   *Number of severely non-orthogonal (> 70 degrees) faces: 462293.
    Non-orthogonality check OK.
  <<Writing 462293 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
    Max skewness = 3.74722 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End
(4) I had to modify the constant/polymesh/boundary in order to define the 'cyclicAMI' interfaces:


Code:
/*--------------------------------*- 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       polyBoundaryMesh;
    location    "1/polyMesh";
    object      boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

17
(
    IF-ROTOR-STATOR
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          25560;
        startFace       12269440;
        matchTolerance    0.001;
        transform    noOrdering;
        neighbourPatch    Volute_Mixing_Interface;
    }
    HUB
    {
        type            wall;
        inGroups        1(wall);
        nFaces          35100;
        startFace       12295000;
    }
    BLADE-FRONT
    {
        type            wall;
        inGroups        1(wall);
        nFaces          7110;
        startFace       12330100;
    }
    BLADE
    {
        type            wall;
        inGroups        1(wall);
        nFaces          54870;
        startFace       12337210;
    }
    SHROUD
    {
        type            wall;
        inGroups        1(wall);
        nFaces          51660;
        startFace       12392080;
    }
    IF-BC-IN
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          29880;
        startFace       12443740;
        matchTolerance    0.001;
        transform    noOrdering;
        neighbourPatch    IF-U-PUMP;
    }
    TIP
    {
        type            wall;
        inGroups        1(wall);
        nFaces          6300;
        startFace       12473620;
    }
    Interface-14
    {
        type            wall;
        inGroups        1(wall);
        nFaces          0;
        startFace       12479920;
    }
    EXTRUSION-inlet-layer
    {
        type            wall;
        inGroups        1(wall);
        nFaces          60;
        startFace       12479920;
    }
    FLUID-INLET-LAYER
    {
        type            patch;
        nFaces          765;
        startFace       12479980;
    }
    Interface-15
    {
        type            wall;
        inGroups        1(wall);
        nFaces          0;
        startFace       12480745;
    }
    TRM_SRF
    {
        type            wall;
        inGroups        1(wall);
        nFaces          5580;
        startFace       12480745;
    }
    EXTRUSION
    {
        type            wall;
        inGroups        1(wall);
        nFaces          2340;
        startFace       12486325;
    }
    IF-U-PUMP
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          1185;
        startFace       12488665;
        matchTolerance    0.001;
        transform    noOrdering;
        neighbourPatch    IF-BC-IN;
    }
    Wall
    {
        type            wall;
        inGroups        1(wall);
        nFaces          97902;
        startFace       12489850;
    }
    Volute_Mixing_Interface
    {
        type            cyclicAMI;
        inGroups        1(cyclicAMI);
        nFaces          12410;
        startFace       12587752;
        matchTolerance    0.001;
        transform    noOrdering;
        neighbourPatch    IF-ROTOR-STATOR;
    }
    Outlet
    {
        type            patch;
        nFaces          1321;
        startFace       12600162;
    }
)
As mentioned earlier, Interface-14 and Interface-15 vanished, as I did a stichMesh operation to connect both Hexa-Meshes (see 1c).


(5) My choice of boundary conditions:
(5a) ./1/U
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    location    "0";
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform (0 0.1 0); 

boundaryField
{
   IF-ROTOR-STATOR
    {
    type        cyclicAMI;
    }
   Interface-14
    {
    type        zeroGradient;
    }
   IF-BC-IN
    {
    type        cyclicAMI;
    }
   Interface-15
    {
    type        zeroGradient;
    }
   EXTRUSION-inlet-layer
    {
    type        fixedValue;
    value        uniform (0 0 0);
    }

   HUB
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    BLADE-FRONT
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    BLADE
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    TIP
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    FLUID-INLET-LAYER
    {
        type            fixedValue;
        value           uniform (0 0.7878 0);

//        type            flowRateInletVelocity;
//        flowRate        0.0138;
//        value           uniform (0 0.7878 0);
    }

    SHROUD
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    TRM_SRF
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    EXTRUSION
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    Wall
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    IF-U-PUMP
    {
    type        cyclicAMI;
    }
    Outlet
    {
    type        zeroGradient;
//    type        pressureInletOutletVelocity;
//    value        $internalField;
    }
    Volute_Mixing_Interface
    {
    type        cyclicAMI;
    }
}
(5b) ./1/p
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 700;

boundaryField
{
FLUID-INLET-LAYER
    {
//        type            fixedValue;
//    value         uniform 0;
    type            zeroGradient;
    }
    IF-ROTOR-STATOR
    {
    type        cyclicAMI;
    }
    Interface-14
    {
    type        zeroGradient;
    }
    IF-BC-IN
    {
    type        cyclicAMI;
    }
    Interface-15
    {
    type        zeroGradient;
    }
    EXTRUSION-inlet-layer
    {
    type        zeroGradient;
    }
    HUB
    {
        type            zeroGradient;
    }
    BLADE-FRONT
    {
        type            zeroGradient;
    }
    BLADE
    {
        type            zeroGradient;
    }
    TIP
    {
        type            zeroGradient;
    }
    SHROUD
    {
        type            zeroGradient;
    }
    TRM_SRF
    {
        type            zeroGradient;
    }
    EXTRUSION
    {
        type            zeroGradient;
    }
    Wall
    {
        type            zeroGradient;
    }
    IF-U-PUMP
    {
    type        cyclicAMI;
    }
    Outlet
    {
//    type        zeroGradient;
        type            fixedValue;
        value           $internalField;

    }
    Volute_Mixing_Interface
    {
    type        cyclicAMI;
    }
}
(5c) ./1/k
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

internalField   uniform 1;

boundaryField
{
FLUID-INLET-LAYER
    {
//    type            fixedValue;
//    value        uniform 3.103e-03;
        type            turbulentIntensityKineticEnergyInlet;
        intensity       0.05;
        value           $internalField;
    }
    IF-ROTOR-STATOR
    {
        type            cyclicAMI;
        value           $internalField;
    }
    Interface-14
    {
        type            kqRWallFunction;
        value           $internalField;
    }
    IF-BC-IN
    {
        type            cyclicAMI;
        value           $internalField;
 
    }
    Interface-15
    {
        type            kqRWallFunction;
        value           uniform 1;
 
    }
    EXTRUSION-inlet-layer
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    HUB
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    BLADE-FRONT
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    BLADE
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    TIP
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    SHROUD
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    TRM_SRF
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    EXTRUSION
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    Wall
    {
        type            kqRWallFunction;
        value           $internalField;
 
    }
    IF-U-PUMP
    {
        type            cyclicAMI;
        value           $internalField;
 
    }
    Outlet
    {
        type            zeroGradient;
//        value           uniform 1;
//        type            inletOutlet;
//        inletValue      $internalField;
//        value           $internalField;

 
    }
    Volute_Mixing_Interface
    {
        type            cyclicAMI;
        value           $internalField;
 
    }
}
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Old   December 13, 2018, 10:02
Default
  #2
jcw
New Member
 
Christian Wolf
Join Date: Mar 2009
Posts: 24
Rep Power: 12
jcw is on a distinguished road
CONTINUED......


(5d) ./1/epsilon
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      epsilon;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -3 0 0 0 0];

internalField   uniform 10;

boundaryField
{
FLUID-INLET-LAYER
    {
//    type            fixedValue;
//    value        uniform 3.79e-03;
        type            turbulentMixingLengthDissipationRateInlet;
        mixingLength    0.005;
        value           $internalField;
    }
    IF-ROTOR-STATOR
    {
        type            cyclicAMI;
//        value           uniform 200;
    }
    Interface-14
    {
        type            epsilonWallFunction;
        value           uniform 200;
    }
    IF-BC-IN
    {
        type            cyclicAMI;
//        value           uniform 200;
 
    }
    Interface-15
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    EXTRUSION-inlet-layer
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    HUB
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    BLADE-FRONT
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    BLADE
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    TIP
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    SHROUD
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    TRM_SRF
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    EXTRUSION
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    Wall
    {
        type            epsilonWallFunction;
        value           $internalField;
 
    }
    IF-U-PUMP
    {
        type            cyclicAMI;
//        value           uniform 200;
 
    }
    Outlet
    {
        type            zeroGradient;
//        value           uniform 200;
//        type            inletOutlet;
//        inletValue      $internalField;
//        value           $internalField;

 
    }
    Volute_Mixing_Interface
    {
        type            cyclicAMI;
//        value           uniform 200;
 
    }
}
(5e) ./1/nut
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    location    "0";
    object      nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -1 0 0 0 0];

internalField   uniform 0.1;

boundaryField
{
FLUID-INLET-LAYER
    {
    type            calculated;
    value        uniform 0;
    }
    IF-ROTOR-STATOR
    {
        type            cyclicAMI;
        value           uniform 0;
    }
    Interface-14
    {
        type            nutkWallFunction;
        value           uniform 0;
    }
    IF-BC-IN
    {
        type            cyclicAMI;
        value           uniform 0;
 
    }
    Interface-15
    {
        type            nutkWallFunction;
        value           uniform 0;
 
    }
    EXTRUSION-inlet-layer
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    HUB
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    BLADE-FRONT
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    BLADE
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    TIP
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    SHROUD
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    TRM_SRF
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    EXTRUSION
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    Wall
    {
        type            nutkWallFunction;
        value           $internalField;
 
    }
    IF-U-PUMP
    {
        type            cyclicAMI;
        value           uniform 0;
 
    }
    Outlet
    {
        type            calculated;
        value           uniform 0;
 
    }
    Volute_Mixing_Interface
    {
        type            cyclicAMI;
        value           uniform 0;
 
    }
}
(6) Because of '462293 non-orthogonal face', I use the following numerical schemes, so that the simulation does not diverge.
(6a) ./system/fvSchemes
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear; //skewLinear;
}

divSchemes
{
//      default         Gauss linear;
      default          Gauss linear skewLinear;
//    default         none;
      div(phi,U)      bounded Gauss upwind;
//      div(phi,U)      Gauss vanLeerV 0 500;
//      div(phi,k)      Gauss limitedLinear 1;
    div(phi,k)    bounded Gauss upwind;
      div(phi,epsilon) bounded Gauss upwind;
    div((nuEff*dev(T(grad(U))))) Gauss linear;
//    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
//    default         none;
//    laplacian(nuEff,U) Gauss linear corrected;
//    laplacian((1|A(U)),p) Gauss linear corrected;
//    laplacian(DkEff,k) Gauss upwind phi uncorrected;
//    laplacian(DkEff,k) Gauss linear corrected;
//    laplacian(DepsilonEff,epsilon) Gauss upwind phi uncorrected;
//    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
//    laplacian(1,p)  Gauss linear corrected;
    default         Gauss linear limited .2;
//default            Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
    interpolate(U)  linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p               ;
}
(6b) ./system/fvSolution
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.0.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver          GAMG;
        tolerance       1e-08;
        relTol          0.05;
//     nPreSweeps      0;
//        nPostSweeps     2;
        smoother        GaussSeidel;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 20;
        agglomerator    faceAreaPair;
        mergeLevels     1;
    }

    U
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        nSweeps         2;
        tolerance       1e-07;
        relTol          0.1;
    }

    k
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        nSweeps         2;
        tolerance       1e-07;
        relTol          0.1;
    }

    epsilon
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        nSweeps         2;
        tolerance       1e-07;
        relTol          0.1;
    }
    Phi
    {
        solver          GAMG;
        smoother        DIC;

        tolerance       1e-06;
        relTol          0.01;
    }
}

SIMPLE
{
    nNonOrthogonalCorrectors 3;
    pRefCell         1000;   //1000;
    pRefValue        0;  //0;

    residualControl
    {
        p               1e-7;
        U               1e-7;
//        nuTilda         1e-5;
    }

}

potentialFlow

{
    nNonOrthogonalCorrectors 3;
}


relaxationFactors
{
    p               0.3;
    U               0.7;
    k               0.3;
    epsilon         0.3;
}
(7) Results:
(7a) The simulation is not diverging, but the results are not matching with measurement data. From paraFoam I see, that there is backflow at the outlet boundary. That is not physical. No need to mention, that pressure raise is not correct. See attached figures.
(7b) Output of Log-file at t=4000.
Code:
Time = 4000

smoothSolver:  Solving for Ux, Initial residual = 6.49334e-05, Final residual = 5.48804e-06, No Iterations 4
smoothSolver:  Solving for Uy, Initial residual = 7.65739e-05, Final residual = 6.41807e-06, No Iterations 4
smoothSolver:  Solving for Uz, Initial residual = 0.000245207, Final residual = 2.17271e-05, No Iterations 4
GAMG:  Solving for p, Initial residual = 0.000497367, Final residual = 1.78079e-05, No Iterations 2
GAMG:  Solving for p, Initial residual = 9.74022e-05, Final residual = 2.70978e-06, No Iterations 3
GAMG:  Solving for p, Initial residual = 2.75499e-05, Final residual = 1.34238e-06, No Iterations 2
GAMG:  Solving for p, Initial residual = 7.57486e-06, Final residual = 2.79618e-07, No Iterations 6
time step continuity errors : sum local = 5.83355e-05, global = 2.4735e-05, cumulative = -0.0134445
smoothSolver:  Solving for epsilon, Initial residual = 0.000195813, Final residual = 4.18956e-06, No Iterations 2
smoothSolver:  Solving for k, Initial residual = 0.000190456, Final residual = 5.48109e-06, No Iterations 2
ExecutionTime = 17569.4 s  ClockTime = 17654 s

fieldValueDelta pressureDifferencePatch write:
    subtract(p) = -736.583

surfaceRegion outlet_avg_p write:
    areaAverage(Outlet) of p = 700

surfaceRegion outlet_avg_ptot write:
    areaAverage(Outlet) of total(p) = 700.748

surfaceRegion inlet_avg_p write:
    areaAverage(FLUID-INLET-LAYER) of p = -36.5828

surfaceRegion inlet_avg_ptot write:
     areaAverage(FLUID-INLET-LAYER) of total(p) = -36.2725
(7c) AMI weights from start of simulation:
Code:
SIMPLE: convergence criteria
    field p     tolerance 1e-07
    field U      tolerance 1e-07

Reading field p

Reading field U

Reading/calculating face flux field phi

AMI: Creating addressing and weights between 25560 source faces and 12410 target faces
AMI: Patch source sum(weights) min/max/average = 0.521354, 1.00613, 0.993977
AMI: Patch target sum(weights) min/max/average = 0.869753, 1.05489, 1.00455
AMI: Creating addressing and weights between 29880 source faces and 1185 target faces
AMI: Patch source sum(weights) min/max/average = 0.505227, 1, 0.996083
AMI: Patch target sum(weights) min/max/average = 1, 1, 1
Does anyone have an idea what is going wrong? I am wondering, why the simulation does not crash even with backflow at outlet? Are the BC reasonable? Is the cyclicAMI interface correct?


Thanks and regards.
Attached Images
File Type: jpg vector.jpg (95.5 KB, 15 views)
File Type: jpg scalarUmag.jpg (34.7 KB, 15 views)
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Old   December 17, 2018, 05:01
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Oh, no one has an idea? Do I have to provide more information?
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Old   December 17, 2018, 06:41
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if backflow is the problem, try using inletoutlet boundary condition for outlet. I don't know about AMI.
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Old   December 17, 2018, 06:57
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Thanks for your reply! Can you please be more precise? Where do I have to define the inletOutlet boundary? In file ./0/U and/or ./0/p? What about k and epsilon?


Regards
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Old   December 17, 2018, 07:29
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for U, K and epsilon use inletOutlet for outlet patch.
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Old   December 19, 2018, 03:12
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Hello!


I tried with inletOutlet boundary condition as mentioned above. Still, the result is unphysical. Fluid flows into the domain at outlet boundary. I wonder, why the simulation does not diverge, as mass cannot be balanced (conservation of mass).


I am not sure, if the use of cyclicAMI interface is correct. I simulate a steady-state, MRF water pump. In order to connect rotor and stator domain, I use the cyclicAMI interface. Is this interface only working with rigid body motion? Is the interface appropriate to connect unconformal (vertices) meshes?
Attached Images
File Type: jpg vector.jpg (106.0 KB, 8 views)
File Type: jpg Umag_scalar.jpg (42.9 KB, 6 views)
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