Mass flow rate
 

Does anyone know how to calculate the mass flow rate at a given cross section in a pipe? It is a simple 2d,axisymmetric,steady flow,constant density problem. What i did was to create a line across the pipe and went to report surface integral to get the mass flow rate. However the value at that surface is not the same as the mass flow rate at the outlet or inlet. By right it should be the same if it obeys continuity equation. Any reason?? Thank you

Re: Mass flow rate
 

Is that line is developed zone? or it may be the cause to turbulence instability(?)

Alamgir