Radial velocities (top panels) and gas mass flow rates (bottom panels) computed in spherical concentric shells, as a function of the shell radius, for the TNG50 (orange) and FIRE-2 (dark red) galaxies. Panels (a) and (d) show the inflow and outflow components separately, panels (b) and (e) show the net (outflow-inflow) flow for all gas phases, panels (c) and (f) show the net flow for the H I alone. The thick lines show the median trend, while the shaded areas show the difference between the 84th and 16th percentile. Negative values indicate inflow.