Is it possible to specify a volumetric flow rate at an OUTLET boundary? Since the density for the fluid changes dramatically, mass flow rate cannot reflect the actual case. Thanks!

Negative inlet is the volumetric flow outlet

putting negative velocity makes solution a bit unstable....aint it?

Sometimes true.

Skin wants volumetric flow const. But why he is doing so is not understood, since there is no conservation of volume law. Even though density changes mass should remain same, whatever may be the volume flow rate. Flow rate should be inforced only on one side. (either inlet or outlet)

Thanks carno and som.

I've tried treat the outlet as inlet with negative velocity. Unfortunately, the solver recognised it as a positive velocity (inflow).