[Elena89]

Hallo everybody,

I'm trying to simulate incompressible flow through turbomachinery with OpenFOAM using pimpleDyMFoam coupled with kOmegaSSt for turbulence modelling.
I've stuck pretty close to the propeller tutorial as to the boundary conditions adjustments.

When I run the case (in parallel as well as in serial) the first approximately 40-50 timesteps work just fine. Then all of a sudden the velocity gets very high and I get a floating point exception (please find log file attached). At least I think that the velocity is the problem...

I've been trying to figure out what causes the problem for several days now and have been trying a lot, but without any success.

I'm pretty sure that it's not a problem with my mesh since check mesh tells me "Ok". It could be something with the fvSchemes or fvSolutions, couldn't it?

Does anyone have any ideas where the problem / error might be? Any help would be greatly appreciated. Thanks in advance

Best regards

Elena

[Artur]

Hi,

Your problem stems from the fact that continuity errors get through the roof pretty quickly:

time step continuity errors : sum local = 3.83444, global = -1.13213, cumulative = -1.60869

After which the solution goes bonkers, which results in the Co exploding, time step decreasing to crazy values and the simulation ultimately failing:

Courant Number mean: 39095.8 max: 1.52799e+11
deltaT = 1.09076e-14
--> FOAM Warning : 
    From function Time::operator++()
    in file db/Time/Time.C at line 1061
    Increased the timePrecision from 6 to 7 to distinguish between timeNames at time 0.431667

Nothing seems to be particularly alarming in your fv files, although 10 correctors seems quite a lot, given most of them don't execute at all (0 iterations in the log). My wild guess would be either the BCs or the mesh in your case causing the issue. If not you could try a smaller time step. Plus, you get some interesting warnings about "switchableNotImpleemnted", which I suspect might have something to do with the problems as well.

All the best,

A