negative pressure

Neel

Hi,

I am tring to model a simple separator (horizontal cylinder)with one inlet and 2 outlets, a multiphase model with air being dispersed and water continuous. The boundary conditions regarding pressure are 1)gas outlet- static pressure= 0 Pa 2)liquid outlet-static pressure= 12000 Pa 3) inlet pressure is governed by flowrates of air and water 4) the domain pressure is 4 bar.

while analysing in cfxpost (streamlines)i get negative pressures. Also, in the output file i get a "notice" which says " a wall has been placed at portions of an outlet boundary condition (at 100%of the faces, 100%of the area) to prevent fluid from flowing into the domain--the fluid is water"

Is it because of this I get negative pressure? or what could be the reason?

Thank you in advance.