[fsaltara]

I am carrying out some simulations of vortex shedding and vortex induced vibration for the case of a 3D circular cylinder at Re=10000 using Smagorinsky LES and the pimpleDyMFoam solver.

I have noticed that, although I am using the 2nd order backward implicit method for the temporal discretization, I must use adaptative time stepping with Courant number below 1.0 to get successful simulations.

I would expect this behaviour with explicit methods.

If Co is greater than 1.0, simulations stop due to large errors. The problem is not related to the convective discretization , because it happens even if I use limited methods like SuperBee.

Even for laminar 2D simulations with Re=200 and the implicit 1st order Euler method I was unable to use large time-steps.

Could someone explain why implicit methods do not allow larger time-steps when running transient vortex induced vibration simulations with OpenFOAM?

Thanks,

Fabio