Vertical profiles of the averaged radial dust and gas velocities (upper three rows) and the dust and gas mass flows (lower three rows) in 3D (left panels) and 2D (right panels) simulations. The Stokes number τ₀ increases from left to right while Z increases from the lower to upper panels. For comparison, in the panels corresponding to Z = 0.01 and τ₀ = 10⁻³ we additionally plot the result of a dust-free simulation. Averages have been taken over the last 400 orbits and over 0.8 ≤ R ≤ 1.2. The dust mass flows are additionally scaled with a factor 1∕ϵ₀ as compared to the gas mass flows. The horizontal axis displays − 2H_g ≤ z ≤ 2H_g in all panels.