Dust size distribution for the fiducial model without the bouncing barrier m2_a4_s4_nobo (left) and with bouncing barrier m2_a4_s4 (right). The blue line is the fragmentation barrier, the green line is the radial drift barrier, and the red line is the bouncing barrier, all computed assuming turbulence to be the dominant driver of relative velocities. The dotted red line is the bouncing barrier if Eqs. (13), (14) are not taken into account. The dashed gray line is the mean grain size, and the dotted lines are plus or minus one standard deviation in log space (see Appendix A.1). The color scale denotes the surface density of the dust σ_d(r, m) = m Σ_d(r, m) in units of grams per square cm² per ln(m).