Synthetic profiles of C IV doublet; all the profiles are normalized to their maximum value. The upper panel compares our reference simulation of a train of blobs (run TR-D11-T300-R10.3) with the case of a continuous stream (run CONT), the case of a single downfalling blob (run 1BL-R10.3), and with the case of a train of blobs with higher density (run TR-D11.7-T300-R10.3). The lower panel compares profiles derived from simulations of a train of blobs differing for the frequency and size of blobs (runs TR-D11-T300-R10.3, TR-D11-T600-R10.3, TR-D11-T150-R10.3, TR-D11-T300-R9.9). The dotted gray lines are the rest positions of the lines of the doublet.