Longitudinal position-velocity (PV) diagrams for the no DW simulation (top) and the DW simulation (bottom). From left to right: v_r for the jet material only, v_r for the surrounding material only, v_z for the jet material only, vz for the surrounding material only, and density stratification. The ordinate of all frames is position along the outflow axis (in au). The color scale in the PVs is scaled by volume × cube of pressure so as to be maximum (in red and yellow shades) for shocked material in the shell, while the color scale for density is in g cm⁻³. Blue curves are predicted velocities in the full mixing hypothesis (Eqs. (16) and (17)), while magenta curves are the predicted immediate-post shock velocities (Eqs. (18) and (19)).