Purely elastic turbulence in channel flows

Turbulence production in wall-bounded parallel shear flows of Newtonian fluids is predominantly located near the bounding walls. In contrast, our recent work [1] demonstrates that in purely elastic turbulence, production is concentrated along the center plane of the channel, away from the walls. This raises the question of what type of production occurs in turbulent flows of non-Newtonian fluids at finite Reynolds numbers, specifically in elasto-inertial turbulence.

In this study, we focus on the zero Reynolds number case in the well-diluted polymer regime. Through a systematic investigation of the dependence on the Weissenberg number (Wi) via direct numerical simulations, we observe the emergence of chaotic motion along the channel midplane, characterised by a rich variety of dynamical states. We further analyse the Wi dependence of velocity statistics and gradient dynamics, revealing a degree of intermittency even in inertialess configurations.

[1] Lellep, M., Linkmann, M., and Morozov, A., “Purely elastic turbulence in pressure-driven channel flows,” Proceedings of the National Academy of Sciences, Vol. 121, No. 9, 2024, pp. e2318851121.