@Flotus1

Could you please help me,

I cant get the real pressure values when I use translational periodic B.C. in my calculations. Is there a way to do it?

Pyhsical meaning of periodic boundary condition
 

First of all, you need to know "what is the periodic boundary condition in CDF?"

This is from Cimbala and Cengel:

"Flow field variables along one face of a periodic boundary are numerically linked to a second face of identical shape (and in most CFD codes, also identical face mesh). Thus, flow leaving (crossing) the first periodic boundary can be imagined as entering (crossing) the second periodic boundary with identical properties (velocity, pressure, temperature, etc."