[Nek5000-users] Outflow bc and pressure

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

Dear neks
When we specify a boundary as outflow "O", I thought we take the normal
stress to be zero

-p*n + mu*(grad(u) + grad(u)^T)*n = 0

which is a natural boundary condition and where n = normal vector. But it
seems that nek sets p=0 on the outflow boundary. So does this mean we on
outflow boundary we take both normal stress to be zero and pressure to be
zero ?

Is it possible to use the normal stress condition without specifying a
pressure ?

Thanks
praveen
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/nek5000-users/attachments/20140527/556a8e25/attachment.html>