[Nek5000-users] Effect of CFL number.

[nek5000-users at lists.mcs.anl.gov]

Dear Neks,

I would like to know what is the effect of CFL number on a turbulence 
simulation in SEM.

I use polynomial order of lx1 = 5 and lxd = 8 and get a C = 0.176 for a 
Re = 2000 with dt = 0.001  in pipe flow where I find a transition to 
turbulence. when I decrease my time step 'dt = 0.0001 ' further my pipe 
becomes fully turbulent for the same mesh.

When I increase the order lx1 = 7 and lxd = 10, I find a completely 
steady solution, instead of a transition to turbulence.

It would be nice what if some could please tell me what parameter 
determines the accuracy of the simulation in terms of a turbulent flow 
because I am not able to reproduce the result with a different mesh or 
with higher order.

Thank you,

Kamal