Velocity direction vertical to wall
 

Hey, guys,

Right now I run a case about air ventilation in room. Pressure base, 3D, boundaries are wall, pressure inlet and pressure outlet. One interesting thing is in the roof(wall) the velocity direction suddenly become vertical. But velocity of the other cells near the wall are normal.

Operating condition: gravity, 9.8 m/s2,

Could anyone help me about this?

Thanks

simpleg