Model DR at t = 400 yr and an inclination angle i = 30°. The results are presented for four different values of the jet and ambient gas mixing degree j_mix (from top to bottom): 0.0, 0.3, 0.6, 1.0. Left: maps of H₂ column density obtained by integration over the velocity range, between + 1 and +150 km s⁻¹. Right: mass–velocity relationship obtained for the molecular gas (black) and the total gas (blue). Bottom panel: (j_mix = 1.0), the green dots correspond to the H₂ swept-up mass–velocity relationship obtained by DC03 (see their Fig. 2). We show the best-fitting power laws m(v) ∝v^−γ to the velocity intervals v ≤10 km s⁻¹ and 10 < v ≲20 km s⁻¹ superposed in red dashed lines. The power-law index γ is given in each panel. The vertical arrows indicate the position of bumps in the total mass–velocity profile (see text).