Experimental insights into elasto-inertial transitions in Taylor–Couette flows

Abstract

Since the seminal work of Taylor in 1923, Taylor–Couette (TC) flow has served as a paradigm to study hydrodynamic instabilities and bifurcation phenomena. Transitions of Newtonian TC flows to inertial turbulence have been extensively studied and are well understood, while in the past few years, there has been an increasing interest in TC flows of complex, viscoelastic fluids. The transitions to elastic turbulence (ET) or elasto-inertial turbulence (EIT) have revealed fascinating dynamics and flow states; depending on the rheological properties of the fluids, a broad spectrum of transitions has been reported, including rotating standing waves, flame patterns (FP), and diwhirls (DW). The nature of these transitions and the relationship between ET and EIT are not fully understood. In this review, we discuss experimental efforts on TC flows of viscoelastic fluids. We outline the experimental methods employed and the non-dimensional parameters of interest, followed by an overview of inertia, elasticity and elasto-inertia-driven transitions to turbulence and their modulation through shear thinning or particle suspensions. The published experimental data are collated, and a map of flow transitions to EIT as a function of the key fluid parameters is provided, alongside perspectives for the future work. This article is part of the theme issue 'Taylor–Couette and related flows on the centennial of Taylor’s seminal Philosophical Transactions paper (part 1)'.

Viscoelastic instabilities of Taylor–Couette flows with different rotation regimes

“…The dynamics of viscoelastic flows away from the threshold should preferably be described by DNS using more elaborated models. Indeed, recent numerical simulations of the viscoelastic fluid using the FENE-P constitutive equation for the polymer contribution, have reproduced some results on inertio-elastic modes and elastic turbulence observed in the experiments [23,25,42,43]. New recents experiments have been performed to investigate inertio-elastic transitions in Taylor-Couette flows [43].…”

Coherent structures of elastoinertial instabilities in Taylor–Couette flows

“…Extensional measurements tend to result in lower relaxation times and therefore lower elasticity numbers (Boulafentis et al. 2023).…”

“…In most reported studies, flow visualisation experiments are commonly employed to elucidate the transitions (Boulafentis et al. 2023). To date, and to the best of our knowledge, no study has experimentally resolved the spatiotemporal flow characteristics of diwhirls and flame patterns, establishing their connection and revealing their link to EIT.…”

Taylor–Couette and related flows on the centennial of Taylor’s seminalPhilosophical Transactionspaper: part 2

“…Part 1 of this two-part theme issue explored contemporary topics related to Taylor-Couette flow including turbulent, convective and two-phase flows as well as extensions to magnetohydrodynamic, ferrofluidic and viscoelastic flows and flow geometries that are closely related to the Taylor-Couette problem [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Part 2 of this theme issue continues with review articles and research articles having their origin in Taylor's 1923 paper.…”