Grid resolved convection, or grid scale noise?

[sss]

Hi,
I'm trying to determine if this is grid resolved convection, or grid scale noise.
This is a plot of max vertical velocity. Colors are +/- 50fpm. The peak to peak distance is approximately 2*dx, which makes me suspect noise. dx is 4km.

[BHajni]

Hi,


Definitely a noise. a) You should reduce time step or use adaptive time step, b) use the diff_6th_opt option. The latter one is a cosmetic solution as it smooths out the disturbances. But the first should resolve some of this issue.

Cheers,
Hajni