Not sure, but IMHO it has something to do with your region definitions. The inlet and outlet regions contain the wall nodes, so there is no no-slip condition in those nodes.
Check:
./simple.py pipe_flow_test_copy.py --save-regions-as-groups --solve-not ./postproc.py -b pipe_7f_long_regions.vtk --layout=row
You might want to change the wall region to:
'select' : 'vertices of surface -f (r.Outlet +v r.Inlet)',and apply the walls condition as the last one by naming it ebc_4, so that is is lexicographically after the inlet and outlet ones.
r.
On 09/19/2016 02:33 PM, Nikhil Vaidya wrote:
Hello!
I am solving for steady laminar flow through a pipe. The issue I am facing is the following:
I have given a velocity boundary condition at the pipe inlet. For the outlet, I examined the following two cases:
Pressure boundary condition at outlet.
No boundary condition prescribed at outlet.
For both cases, I get a strange jump in the velocity at the pipe outlet. In the attached files you can see the velocity and pressure plotted along the axis(from inlet to outlet) of the pipe. Why do I see a jump in the velocity for both cases? How do I specify outlet conditions in sfepy?
Another observation that I have made is that for case 1, there is a jump in the pressure value at the outlet. In case 2, this pressure-jumps goes away.
Best regards, Nikhil