[Nek5000-users] neuman bc for the normal velocity component

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

Dear Nekians,

I'm relatively new to nek.

I would like to
compute the flow of a boundary layer and
I would like to impose the following
boundary condition on the top (2D) boundary,
which is parallel to the wall:

u = U_base and dv/dy = - dU_base/dx,

where U_base is the known inviscid base flow.
The velocity component u is parallel to
the boundary, whereas v is normal.

I tried to use 'ON ' but this did not give
the result I was expecting (Am I doing smth. wrong?).
At the boundary nodes u was equal to U_base, but
at the very next node u was completly different
(and v was of course completly wrong).

Thanks for any help

Joris