Normal to Boundary or Direction Vector?
 

Hi Everyone.

I have attached a picture of my geometry.
On the top part of my geometry is the pressure outlet and the bottom two is the mass flow rate inlets.

I'm currently using direction vector (+ve Y direction) for both pressure outlet and mass flow rate inlets for my boundary condition. Should I use normal to boundary or direction vector? And any idea on how would they differ?

Thanks in advance!

1, It seems that in your case, the direction, normal to boundary is similar to the direction, normal to direction vector. both of them are +ve Y direction).

2, I think the difference is based on how you inlet or outlet boundary is placed in your geometry.

Thank you!