[petsc-users] GAMG parallel convergence sensitivity

[Jed Brown]

Mark Lohry <mlohry at gmail.com> writes:

> It seems to me with these semi-implicit methods the CFL limit is still so
> close to the explicit limit (that paper stops at 30), I don't really see
> the purpose unless you're running purely incompressible? That's just my
> ignorance speaking though. I'm currently running fully implicit for
> everything, with CFLs around 1e3 - 1e5 or so.

It depends what you're trying to resolve.  Sounds like maybe you're
stepping toward steady state.  The paper is wishing to resolve vortex
and baroclinic dynamics while stepping over acoustics and barotropic
waves.