Vertically integrated dust density distribution with a fixed value of length scale of f = 1, for A = 0.1 (left column) and A = 0.3 (right column) at different times 0.5 Myr, 1.0 Myr, 3.0 Myr, and 5.0 Myr from top to bottom, respectively. The solid white line shows the particle size corresponding to a Stokes number of unity. The blue line represents the fragmentation barrier according to Eq. (15).