Dust density distribution. Top panels: Dust density distribution vertically averaged at 350 orbits in the ϕ − R plane. The large grains are 100 μm (blue), 500 μm (green), and 1 mm (orange). The small grains spanning 0.1–30 μm are plotted as a black shade in the disk and are assumed to be well coupled with the gas. Bottom panels: Same dust density distribution as the top panels but viewed in the Z − R plane and averaged in the azimuthal direction.