[yanyanh]

Hi guys,

I'm currently doing some research on wall functions with a empty 2D domain.
The Mesh is generated by blockmesh and the simpleFoam solver ist used. Everything is working well in parallel and serial, but if I turn on the Grading in the z-direction (perpendicular to the ground) the Solver crashes producing this Error message:

Time = 1

smoothSolver: Solving for Ux, Initial residual = nan, Final residual = nan, No Iterations 1000
smoothSolver: Solving for Uz, Initial residual = nan, Final residual = nan, No Iterations 1000
GAMG: Solving for p, Initial residual = nan, Final residual = nan, No Iterations 1000
time step continuity errors : sum local = nan, global = nan, cumulative = nan
smoothSolver: Solving for epsilon, Initial residual = nan, Final residual = nan, No Iterations 1000
smoothSolver: Solving for k, Initial residual = nan, Final residual = nan, No Iterations 1000
ExecutionTime = 0.53 s ClockTime = 1 s



--> FOAM FATAL IO ERROR:
wrong token type - expected Scalar, found on line 0 the word 'nan'

file: /local/huangya/OpenFOAM/huangya-2.2.0/run/foam/2d_mesh_para_empty_grading/system/data.solverPerformance.U at line 0.

From function operator>>(Istream&, Scalar&)
in file lnInclude/Scalar.C at line 91.

FOAM exiting


This happens only for the grading in z-direction and not for the x-direction. Are there any limitations that I missed using simpleFoam with graded meshs?

Thanks for your time!

[Lieven]

Dear Yanyan,

Welcome to the forum! For us to help us, you should provide a little bit more information.
Could you give us the output of 'checkMesh'? Which are the boundary conditions that you impose? What are the discretization schemes (fvSchemes)?

Cheers,

Lieven

[yanyanh]

Hi Lieven,

Here is the output of CheckMesh:

Mesh stats
    points:           3402
    internal points:  0
    faces:            6500
    internal faces:   3100
    cells:            1600
    faces per cell:   6
    boundary patches: 5
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     1600
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points   Surface topology                  
    outlet              20       42       ok (non-closed singly connected)  
    sides               3200     3402     ok (non-closed singly connected)  
    inlet               20       42       ok (non-closed singly connected)  
    ground              80       162      ok (non-closed singly connected)  
    top                 80       162      ok (non-closed singly connected)  

Checking geometry...
    Overall domain bounding box (0 0 0) (5000 1 500)
    Mesh (non-empty, non-wedge) directions (1 0 1)
    Mesh (non-empty) directions (1 0 1)
    All edges aligned with or perpendicular to non-empty directions.
    Boundary openness (-5.67186378575e-21 -6.11290791373e-16 0) OK.
    Max cell openness = 1.35710844948e-16 OK.
    Max aspect ratio = 9.98190321022 OK.
    Minimum face area = 6.26133099908. Maximum face area = 3913.33187443.  Face area magnitudes OK.
    Min volume = 391.333187443. Max volume = 3913.33187443.  Total volume = 2500000.  Cell volumes OK.
    Mesh non-orthogonality Max: 0 average: 0
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 3.63068469086e-13 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End

and fvSchemes:

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

ddtSchemes
{
    default             steadyState;
}

gradSchemes
{
    default             Gauss linear;
}

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

laplacianSchemes
{
    default             Gauss linear limited corrected 0.333;
}

interpolationSchemes
{
    default             linear;
}

snGradSchemes
{
    default             limited corrected 0.333;
}

fluxRequired
{
    default             no;
    p;
}


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

It's quite standard. I took the turbineSiting tutorial file and modified it. So I deleted the two disks and used empty type boundary for the sides.

Thanks!

[yanyanh]

I solved the problem. There was a mistake with the BC at the Inlet.