Dust-to-gas volume density ratio ρ_d∕ρ_g as a functionof r and z (upper panels) as well as dust-to-gas surface density ratio Σ_d∕Σ_g as functions of r and t (lower panels). The upper panels show the spatial dust distribution 5 kyr after the dust initialization. We compare a simulation in which the turbulence in the dust layer is driven by the streaming instability (left panels) and two simulations in which the vertical shear instability is the main source of turbulence (middle and right panels). For the same dust-to-gas surface density ratio of Z =0.02, the dust scale height is smaller, but the radial dust concentration is weaker in the former case. (The values of Z are specified in the titles.) In the latter case, more dust is accumulated in overdensities if the surface density ratio is higher. Some of the accumulations are sufficiently dense for their radial drift to cease almost entirely.