Dust density distribution at different times of evolution (upper panel) and real part of the visibilities at 870 μm (bottom panel) at different times of dust evolution, when no planet is embedded in the disk. ALMA Cycle 0 data at this wavelength are over-plotted (data from Walsh et al. 2014). In the upper panel, the white and blue line correspond to a_drift (Eq. (10)), and a_frag (Eq. (9)), respectively.