Under the
Limitations for Modeling Streamwise-Periodic Flow heading, the last bullet item is not accurate:
Discrete phase and multiphase modeling are not allowed.
It should be replaced with
Steady particle tracks can be modeled only if the particles have a possibility to leave the domain without generating incomplete trajectories.
While Eulerian multiphase can be modeled with translational periodic boundary conditions, you cannot use the mass flow rate specification method. However, you can specify a constant pressure gradient.