[Nek5000-users] Outflow BC with negative velocity

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

Dear all,

I've been having some trouble with the outflow BCs in an axisymmetric 
case with periodic velocity inflow conditions. Inflow velocity takes 
these values:

ux=(sqrt(2.)/5.)*sin(2.*pi*0.03*time)

It runs fine at Re=1000, but when set to Re=13329, which is the value 
I'm interested in testing, it crashes due to backflow near the boundary 
(with outflow BC). Is there any setting that allows the outflow to 
handle flow in both ways? I have already tried turb_outflow (trying to 
eliminate the negative flow), but it's not working properly with the 
axisymmetric condition.

Thanks in advance for the help,

MViturro