mass imbalance

novice

hi,

i am solving the stator-rotor problem with superheated steam. the problem is the residuals are of the order of 1e-5 but the mass imbalance keeps oscillating, going up and down and not at all balancing. i am using coupled/implicit solver. i ran the analysis for quiet a long time.

Which kind of BC is best suited for these kind of problems. i am giving total pressure inlet and static pressure outlet.

Can anyone kindly help me out in this? Is there any general methodology for solving these kind of problems?

Thanks in advance.