Elasto-inertial transitions in particle-laden viscoelastic Taylor-Couette flow*

The Taylor-Couette flow of dilute to semi-dilute suspensions of neutrally buoyant spherical particles in viscoelastic base polymer solutions is investigated. Friction measurement are synchronized with flow visualisation to characterize the critical conditions for the onset of elasto-inertial regimes. Lower particle volume fractions do not affect the nature of the primary transition to elastoinertial turbulence (EIT), even reducing the critical Weissenberg number for the onset of EIT, despite a decrease in the apparent fluid elasticity. For semi-dilute particle volume fractions, an apparent relaminarization occurs with yet not further decrease in fluid elasticity. A new regime termed here Elasto-Inertial Dissipative replaces EIT. Increasing particle volume fraction in the semi-dilute regime delays the onset of EID similarly to what was observed previously for EIT in lower elasticity fluids. After the onset, a decrease in the pseudo-Nusselt number observed with increasing inertia and particle-to-polymer concentration ratio confirms a particle-induced alteration of energy transfers in the flow.