[Denao]

Hi all,

I was hoping for some pointers. I have a case where I am trying to do some resistance predictions of a ship hull. The case runs fine using interFoam and seems to produce reasonable results.

If i try and run the same case with interDyMFoam the solution very quickly blows up, with the pressure forces becoming massive and the time step reducing so far as to cause a floating point exception.

I have also tried achieving a steady state with interFoam before continuing the run with interDyMFoam, with the same results.

My dynamicMeshDict is below, please let me know if there are any other outputs that would be useful:

DynamicFvMesh       dynamicMotionSolverFvMesh;

motionSolverLibs    ("libsixDoFRigidBodyMotion.so");

motionSolverLibs    ("libsixDoFRigidBodyMotion.so");

solver              sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{
    patches         (hull);
    innerDistance   0.3;
    outerDistance   1;

    centreOfMass    (3.97 0 0.65);
    mass            10900;
    momentOfInertia (40 921 921);
    rhoInf          1;
    report          on;
    accelerationRelaxation 0.9;
    value           uniform (0 0 0);
value           uniform (0 0 0);

    constraints
    {
        zAxis
        {
            sixDoFRigidBodyMotionConstraint line;
            direction     (0 0 1);
        }
        yPlane
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis          (0 1 0);
        }
    }

    restraints
    {
        translationDamper
  {
        translationDamper
        {
            sixDoFRigidBodyMotionRestraint linearDamper;
            coeff         8596;
        }
        rotationDamper
        {
            sixDoFRigidBodyMotionRestraint sphericalAngularDamper;
            coeff         11586;
        }
    }
}

[AnasCFD]

Hello,
I am facing the same problem with interFoam & interDyMFoam for a 2D case. Could you manage to solve your problem?.
Your feedback is highly appreciated.

[federicabi]

Hello everybody,
I'm trying to simulate a similar case but I have convergence troubles also with interFoam in OF 3.0.1. I imported the mesh from Star CCM+ with ccm26ToFoam and checkMesh gave me one error about max skewness on 17 cells in a region out of my interest(my mesh has about 800000 cells) so I did not consider this error (should I?).
I also set up a k-eps turbulent model.
Once I run the case, it diverges after few time steps giving unreasonable forces. I can't keep the Co number under 1 even with adjustableTimeRun option and alpha.water under 1.
I attach my dictionaries.

I appreciate your precious help.

Federica