Friction dynamics of elasto-inertial turbulence in Taylor-Couette flow of viscoelastic fluids.

Dynamic properties of elasto-inertial turbulence (EIT) are studied in a Taylor-Couette geometry. EIT is a chaotic flow state that develops upon both non-negligible inertia and viscoelasticity. A combination of direct flow visualization and torque measurement allows to verify the earlier onset of EIT compared with purely inertial instabilities (and inertial turbulence). The scaling of the pseudo-Nusselt number with inertia and elasticity is discussed here for the first time. Variations in the friction coefficient, temporal frequency spectra and spatial power density spectra highlight that EIT undergoes an intermediate behaviour before transitioning to its fully developed chaotic state that requires both high inertia and elasticity. During this transition, the contribution of secondary flows to the overall friction dynamics is limited. This is expected to be of great interest in the aim of achieving efficiency mixing at low drag and low but finite Reynolds number. This article is part of the theme issue "Taylor-Couette and related flows on the centennial of Taylor's seminal paper (Part 2)".