[gush]

i am dealing with DPM for a while.

my study case is simple for now. inert particles 2 micro meter. there is an enclosure with one inlet and two outlets.

in injection section i set the flow are as 1,47*10^-11 kg/s
and in this case inlet concentration would be flow rate/velocity/area ? am i wrong?
and this value is (1,47e-11)(kg/s) / (0,111 m/s) / (0,0016 m2)=8,28e-08 kg/m3

but after the DPM iteration reports says the inlet concentration is 8,47e-08 kg/m3.

how can it be?? i solved some other similar cases and everytime there is a 2-3% difference between the set value and report!