Tollmien-Schlichting route to elastoinertial turbulence in channel flow

Elastoinertial turbulence (EIT) in dilute polymer solutions displays tilted sheets of polymer stretch with weak spanwise-oriented flow structures -- a sharp contrast to the three-dimensional quasistreamwise vortex structures that make up inertia-driven Newtonian turbulence. We show that at for channel flow at sufficiently high Reynolds number, the Newtonian nonlinear Tollmien-Schlichting (TS) wave evolves continuously into EIT as the Weissenberg number increases, highlighting in particular a ``sheet-shedding'' process by which individual sheets are born in the Kelvin cat's eye structure of the TS wave and break up to form the layered multi-sheet structure characteristic of EIT.