[alex_rubel]

Hi
I'm new with OpenFoam and I done a bit of CFD with CFX before.
I doing a quite simple study about a submarine (without appendages) in OF 1.6.
I'm using simpleFoam but for the moment I get quite bad results, and convergence problems.
My inlet speed is 3.5 m/s and my mesh is around 6millions elements with a Y+ around 10. (this Mesh gives me very good results in CFX) The checkMesh is OK :

Mesh stats
    points:           6238133
    faces:            18602584
    internal faces:   18491528
    cells:            6182352
    boundary patches: 4
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     6182352
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition 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                  
    SURFACE_HULL        38368    38370    ok (closed singly connected)      
    SURFACE_SIDE        46288    46464    ok (non-closed singly connected)  
    SURFACE_OUTLET      17600    17689    ok (non-closed singly connected)  
    SURFACE_INLET       8800     8889     ok (non-closed singly connected)  

Checking geometry...
    Overall domain bounding box (-7.696 -8.712 -8.712) (21.78 8.712 8.712)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (-5.04721e-17 2.96585e-16 3.75431e-17) OK.
    Max cell openness = 7.73145e-15 OK.
    Max aspect ratio = 496.544 OK.
    Minumum face area = 1.83581e-08. Maximum face area = 0.376178.  Face area magnitudes OK.
    Min volume = 6.63038e-12. Max volume = 0.102174.  Total volume = 6329.87.  Cell volumes OK.
    Mesh non-orthogonality Max: 61.2197 average: 9.26162
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 2.01934 OK.

Mesh OK.

I'm using kOmegaSST model.
I use potentialFoam then lunch the simpleFoam without turbulences and finally set the turbulences on.

I set the following relaxation factors

relaxationFactors
{
    p               0.3;
    U               0.7;
    k               0.5;
    omega           0.5;
    R               0.7;
    nuTilda         0.7;
}

I'm also using kqRWallFunction, omegaWallFunction and nutWallFunction in the hull BC.


I got a lot of question with no answers :
1/ Am I using a good scheme (potential,turb off, turb on) to solve my problem ?
2/ Should I use WallFunction or fixedValue (0) for my hull BC (omega,k,nut) ?
3/ Should I use nNonOrthogonalCorrectors ?
4/ Is my relaxation factors good ?
5/ Do you have any idea to help me ?


Tanks a lot
Alex