[immortality]

whats incorrect in this case?
it seems there is a limit on output pressure that below that solution gives non correct solution on the outlet mainly on neighbors.
the tube is filled by a high pressure fluid(1800000 I used here) and opening has a lower pressure.it seems where this pressure on BC goes lower than a value it gives improper results(internalField values shouldn't be lower than the boundary)but I don't know whats this pressure limit.
has had anyone of CFD fans! such an experience or have knowledge about?(maybe a gasdynamic rule there is for it)