I am simulate a air-condition in car. At the exit, I set it as pressure outlet boundary. There exist backflow at the exit. In actual ,there should be no backflow. What is the cause

Hi buffalo,

have you tried to reduce the turbulence indensity at the outlet? what about the inlet conditions? turbulence at the inlet could reflect at short investigation areas turbulence and therefore backflow at the outlet. Just some ideas from Ed