  Turbulence is ubiquitous in nature yet even for the case of ordinary
Newtonian fluids like water our understanding of this phenomenon is limited.
Many liquids of practical importance however are more complicated (e.g. blood,
polymer melts or paints), they exhibit elastic as well as viscous
characteristics and the relation between stress and strain is nonlinear. We
here demonstrate for a model system of such complex fluids that at high shear
rates turbulence is not simply modified as previously believed but it is
suppressed and replaced by a new type of disordered motion, elasto-inertial
turbulence (EIT). EIT is found to occur at much lower Reynolds numbers than
Newtonian turbulence and the dynamical properties differ significantly. In
particular the drag is strongly reduced and the observed friction scaling
resolves a longstanding puzzle in non-Newtonian fluid mechanics regarding the
nature of the so-called maximum drag reduction asymptote. Theoretical
considerations imply that EIT will arise in complex fluids if the extensional
viscosity is sufficiently large.
