[Nek5000-users] ON boundary condition

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

Hi Paul

Thank you for info. I'm using ON at the top of my box for jet in
crossflow (it was originally in the setup I've got from Milos and I
simply didn't change it) and it seem to work fine (I use Pn-Pn-2). My
bigger problem is an outflow. I'm using O, but in many cases it gives
reflections that trigger spurious oscillations, so I was looking for
something better. To avoid this problem I run my simulations in the long
box with an outflow 150 away from the pipe. It's a lot comparing to 60
in simson. Every run with the distance smaller than 100 gives
nonphysical solutions. Is there in nekton some good non reflecting
boundary condition?
Best regards

Adam

On Wed, 2012-02-15 at 08:33 -0600, nek5000-users at lists.mcs.anl.gov
wrote:
> Hi Adam,
> 
> I set up ON bc some years back to support Blasius boundary layer
> analysis in which the tangential (streamwise) velocity is
> prescribed and the wall-normal velocity is allowed to escape
> as the velocity boundary layer thickens.  This also implies
> that the pressure is fixed on the upper surface.   This feature 
> was developed  for Pn-Pn-2 and hasn't been extensively tested
> in many years.   If this is a feature that you need, we could
> look into resurrecting it.  (Note that the "escaping" feature
> implies that the surface is aligned with either x,y, or z, and
> not inclined w.r.t. these principal axes.)
> 
> Cheers,
> 
> Paul
> 
> 
> 
> On Tue, 14 Feb 2012, nek5000-users at lists.mcs.anl.gov wrote:
> 
> > Hi all
> >
> > I try to find some information about ON boundary condition in nekton.
> > What is the difference between O and ON?
> > Regards
> >
> > Adam
> >
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