[Nek5000-users] Uservp, eddy diffusivity and explvis
nek5000-users at lists.mcs.anl.gov
nek5000-users at lists.mcs.anl.gov
Sun Jul 18 16:37:11 CDT 2010
Howdy,
I was trying to test an eddy viscosity model for an internal flow
problem with heat transfer - set up very similar to turbChannel. The
domain contains a stagnating region, from which the attached picture
shows a slice (flow in x from left, wall at bottom and right side is
also wall, the flow goes around this cylinder in/out of the
in-plane/y-direction).
The viscosity computation kicks in after the 2nd time step, before that
diffusivity is just equal param(2) (rho is unity). What happens though
is that as soon as I start the simulation with uservp (param 30 > 0),
the velocity goes nuts in the stagnation region, starting from step 0,
even though viscosity does not (yet) change.
After some debugging, I found that this behavior is caused by the
following line which I took from turbChannel:
"if(ifsplit .and. param(30).gt.0) ifexplvis = .true."
ifsplit is true in my case, so this condition is met and yields the
weird behavior as seen in the plot.
When I comment it out, however, everything seems normal and even the
eddy viscosity computation seems to work well, although I haven't done
long term testing yet.
What would you advise me to do? I am using rev548.
Thanks,
Markus
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