Mass flow and U-Mom flow in CFX

Zhihua Xie

Hi all,

I have specified a regular peoriodic velocity U as an inlet boundary condition on a face. When I monitored the mass flow and U-Mom flow on that face, the plot of mass flow is regular peoriodic as the same as the velocity, but the plot of U-Mom flow on that face is irregular. I just wondered if the velocity on the inlet boundary is given, why the U-Mom flow is different from the input value? I have looked through the help documents but failed to find any information about the mass and U-Mom flow. Does any one know the formula in CFX to calculate the mass flow and U-Mom flow on the boundary? Thank you very much in advance!