Radial velocity of the angle-averaged shock radius, , as a function of radius for our eight 3D models grouped in panels according to the respective progenitor model: W15 (top left), L15 (bottom left), N20 (top right), and B15 (bottom right). In each panel, we also display the corresponding distribution of ρr³ inside the progenitor star (black dotted line), where the scale given on the righthand side of the plot. The radii of the C+O/He and He/H composition interfaces in the progenitor star (defined in Sect. 2.1) are indicated by the vertical dash-dotted lines.