Evolution of the bulk velocity v_y of the tidal tail along the direction y at selected times as indicated by solid or dotted lines. Left panel: model C10G13. The blue dashed line indicates the analytical solution given by Eq. (19) at t = 168 Myr. Right panel: model C10W1. The vertical dashed lines represent the positions of y_C according to Küpper et al. (2008). The epicyclic overdensities, which develop near the predicted positions ±240 pc at 400−600 Myr, are places where stars slow down or even reverse their motion (i.e. move towards the cluster).