Hi!

I need to model a Francis turbine with spiral housing, 18 guide vanes, 15 rotor blades and the draft tube.

To save the time I want to do the problem with periodic conditions. here comes the problem. I have to model the whole spriral casing, 1/18th of the guide vanes, 1/15th of the impeller and the whole draft tube. The simulation seams to work ok (it converges and I get ok resuls) but when I look at the flow field I see that it only consideres the flow trough one periodic section. In other words - I have assimetric velocity field at the inlet into the draft tube (flow only under the impeller section and no flow elswhere). How do I need to define the periodic surfaces and the interfaces between the sections to get the simulation to run properly? I think there must be some trick when interfaces are defined but I'm not really sure.

Thanks for responces, Mateus

Solved the problem!

Thanks anyway...

MAteus