[Nek5000-users] 3D v/s. 2D computation

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

Dear All,

  I am carrying out 3D simulations using NEK5000 in a hexahedral domain.
Symmetry boundary conditions have been imposed on the side wall and
stress free conditions are prescribed on the top and bottom boundary.
At the inlet and outlet, Dirichlet and stress free conditions are used, 
respectively.

  I observe that the flow on the symmetry plane is different from that 
obtained via
2D simulation. Is this a numerical artifact (increased diffusion because 
of 3D mesh)
or is it physical? If I increase the resolution of the mesh in third 
dimension,
do I expect to get the 2D simulation results on the symmetry plane?

  Any input will be appreciated.

Many thanks,
NN.