Gas density (colourmap) and velocity streamlines (cyan arrows) of the 2D toy model. The lines thickness is proportional to the velocity ‖υ‖. The outflow inclination, width and averaged intensity are fixed and equal respectively to i = 40^∘, δ = 0.7H, and Ω_w = 6 × 10⁻³ Ω. The density is Gaussian in z and has a cosine perturbation in x with amplitude A_x = 0.5. The outflow configuration can be directly compared with that of Fig. 9 (here the plume has been shifted towards the centre of the 2D domain).