[Nek5000-users] SYM boundary conditions

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

Hi Neks,

I am looking for a boundary condition that leads the flow to go out or 
to go into the domain.

Is 'SYM' valid for this purpose?


I think that what I am looking for is, in the outlet surface:

   - If the velocity vector at the outlet points out of the domain, then 
the boundary condition for the velocity will be of the Neumann type

   - However, if the velocity at the outlet points into the domain, then 
we can imagine that the outflow is no longer an outflow, but an inflow, 
and that we therefore would like to specify a Dirichlet boundary 
condition for velocity


Thanks in advance
SL