Left: evolution of the global minimum in dust density with time for all 4 dust fluids in a simulation with δ = 0.01 and κ = 0.7968. The size of the assumed particles in the fluid increases from dust 1 to 4. After the end of the linear phase (t ~ 10), the global minimum decreases exponentially. The decrease is faster for heavier dust particles. Only the part of the simulation is shown, where all minima are above the allowed minimum density (see Sect. 2.1). Right: global maximum for the four dust species. Density increases are stronger for heavier dust species.