negative pressure!
 

hiii!!! i m working on arteries which has plague in it (geometry appears to be same as a pipe having a converging section in the middle).. i m simulating it in Fluent (release 13.0). i have set the velocity inlet boundary condition as 0.33 m/sec and pressure outlet boundary condition as 0 since it a gauge pressure. i m getting negative pressure at the converging section and at the walls of the diverging section also...i don't want it to be negative as the fluid will be pushed back owing to this..so i need some of your suggestions which will help me to get positive pressure.