  Instabilities in free surface continuous jets of non-Newtonian fluids,
although relevant for many industrial processes, remain less well understood in
terms of fundamental fluid dynamics. Inviscid, and viscous Newtonian jets have
been studied in great detail; buckling instability in viscous jets leads to
regular periodic coiling of the jet that exhibits a non-trivial frequency
dependence with the height of the fall. Very few experimental or theoretical
studies exist for continuous viscoelastic jets beyond the onset of the first
instability. Here, we present a systematic study of the effects of
viscoelasticity on the dynamics of free surface continuous jets of surfactant
solutions that form worm-like micelles. We observe complex nonlinear
spatio-temporal dynamics of the jet and uncover a transition from periodic to
doubly-periodic or quasi-periodic to a multi-frequency, possibly chaotic
dynamics. Beyond this regime, the jet dynamics smoothly crosses over to exhibit
the "leaping shampoo effect" or the Kaye effect. This enables us to view
seemingly disparate jetting dynamics as one coherent picture of successive
instabilities and transitions between them. We identify the relevant scaling
variables as the dimensionless height, flow rate, and the elasto-gravity number
and present a regime map of the dynamics of the jet in terms of these
parameters.
