[toru]

Hi,
I am trying to simulate liquid behavior around a rotating object using the solver "interFoam".
The problem is that a calculation always diverges. I suspect the reason is a very small gap in the model (though the small gap is necessary for my task.).
The small gap induces a large difference of a mesh size in the model. I ended up with no solutions for this problem though I have repeated the calculation with many different conditions including different mesh sizes.
I would really appreciate if you give me some advice or hints.

1. Model description
   
   Model type: 2D
   
   <Calculation area>
   Shape: rectangular
   Size: 1000 mm * 1600 mm
   
   <Rotating object>
   Shape and size of the rotating object: circle (cylinder in 3D), 400 mm in diameter
   Circumferential speed: 30 m/s
   Position: the rotating object is placed at the position where the distance between its circumference and the bottom edge of the calculation area becomes 0.1 mm.
   • the model picture
     1.jpg
   • the detail pictures showing the position where the gap is 0.1 mm
     2.jpg
     3.jpg
   
   <Liquid>
   Type: water
   Initial condition: Initially no liquid exist in the area. It is supplied through a nozzle placed near the rotating object. The initial speed is 20 m/s.
   
   <Solver, Turbulence model>
   interFoam, k-epsilon
   
   
2. Problematic results
   • Last snaps before the calculation has diverged (3 msec after an initial state).
     4.jpg
     5.jpg
   
   
3. Some codes
   • controlDict
     

     /*--------------------------------*- C++ -*----------------------------------*\
     | =========                 |                                                 |
     | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
     |  \\    /   O peration     | Version:  v1606+                                |
     |   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
     |    \\/     M anipulation  |                                                 |
     \*---------------------------------------------------------------------------*/
     FoamFile
     {
         version     2.0;
         format      ascii;
         class       dictionary;
         location    "system";
         object      controlDict;
     }
     // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
     
     application     interFoam;
     
     startFrom       latestTime;
     
     startTime       0;
     
     stopAt          endTime;
     
     endTime         1;
     
     deltaT          0.000001;
     
     writeControl    adjustableRunTime;
     
     writeInterval   0.001;
     
     purgeWrite      0;
     
     writeFormat     ascii;
     
     writePrecision  6;
     
     writeCompression uncompressed;
     
     timeFormat      general;
     
     timePrecision   6;
     
     runTimeModifiable yes;
     
     adjustTimeStep  on;
     
     maxCo           1;
     maxAlphaCo      1;
     
     maxDeltaT       1;
     
     
     // ************************************************************************* //

   • fvSchemes
     

     /*--------------------------------*- C++ -*----------------------------------*\
     | =========                 |                                                 |
     | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
     |  \\    /   O peration     | Version:  v1606+                                |
     |   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
     |    \\/     M anipulation  |                                                 |
     \*---------------------------------------------------------------------------*/
     FoamFile
     {
         version     2.0;
         format      ascii;
         class       dictionary;
         location    "system";
         object      fvSchemes;
     }
     // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
     
     ddtSchemes
     {
         default         Euler;
     }
     
     gradSchemes
     {
         default         Gauss linear;
     }
     
     divSchemes
     {
         div(rhoPhi,U)   Gauss linearUpwind grad(U);
         div(phi,alpha)  Gauss vanLeer;
         div(phirb,alpha) Gauss linear;
         div(phi,k)      Gauss upwind;
         div(phi,epsilon) Gauss upwind;
         div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
     }
     
     laplacianSchemes
     {
         default         Gauss linear corrected;
     }
     
     interpolationSchemes
     {
         default         linear;
     }
     
     snGradSchemes
     {
         default         corrected;
     }
     
     
     // ************************************************************************* //

   • fvSolution
     

     /*--------------------------------*- C++ -*----------------------------------*\
     | =========                 |                                                 |
     | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
     |  \\    /   O peration     | Version:  v1606+                                |
     |   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
     |    \\/     M anipulation  |                                                 |
     \*---------------------------------------------------------------------------*/
     FoamFile
     {
         version     2.0;
         format      ascii;
         class       dictionary;
         location    "system";
         object      fvSolution;
     }
     // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
     
     solvers
     {
         "alpha.water.*"
         {
             nAlphaCorr      2;
             nAlphaSubCycles 1;
             cAlpha          1;
     
             MULESCorr       yes;
             nLimiterIter    2;
     
             solver          smoothSolver;
             smoother        symGaussSeidel;
             tolerance       1e-8;
             relTol          0;
         }
     
         pcorr
         {
             solver          PCG;
             preconditioner  DIC;
             tolerance       1e-5;
             relTol          0;
         }
     
         p_rgh
         {
             solver          PCG;
             preconditioner  DIC;
             tolerance       1e-07;
             relTol          0.05;
         }
     
         p_rghFinal
         {
             $p_rgh;
             relTol          0;
         }
     
         "(U|k|epsilon).*"
         {
             solver          smoothSolver;
             smoother        symGaussSeidel;
             tolerance       1e-06;
             relTol          0;
             minIter         1;
         }
     }
     
     PIMPLE
     {
         momentumPredictor   yes;
         nOuterCorrectors    200;
         nCorrectors         1;
         nNonOrthogonalCorrectors 0;
         turbOnFinalIterOnly false;
         residualControl
         {
             U
             {
                 tolerance 1e-5;
                 relTol    0;
             }
             p_rgh
             {
                 tolerance 5e-4;
                 relTol    0;
             }
             alpha.water
             {
                 tolerance 1e-2;
                 relTol    0;
             }
         }
     }
     
     relaxationFactors
     {
         fields
         {
             p_rgh      0.3;
             p_rghFinal 1;
         }
         equations
         {
             "U|k|epsilon"     0.3;
             "(U|k|epsilon)Final"   1;
         }
     }
     
     // ************************************************************************* //