Elasto Inertial Turbulence: A Numerical Discovery

Abstract: Elasto inertial turbulence (EIT) is a chaotic state os polymer flows, first discovered in numerical simulations of channel flows. The process behind the discovery of EIT provides critical information about the physics at play. The polymer model most commonly used for simulation of drag reduction with polymer additives, the FENE-P model, is notoriously hyperbolic, or stiff. Using appropriate numerical methods and resolutions not only revealed the existence of the phenomenon, it led to the identification of the key scales involved in the self-sustaining cycle of EIT. This seminar will present the current state of knowledge of EIT, including the different regimes (see Figure), a first coherent structure, and its existence in natural convection flows. The mechanism of EIT will be discussed in the context of energy transfer between polymers and flow. The talk will end on a few remarks about the possible connection between EIT and elastic turbulence, a chaotic state observed in inertialess flows.