Vortex merging and splitting: A route to elastoinertial turbulence in Taylor-Couette flow

Abstract

Experimental evidence is reported of a new merge-split transition (MST) to elastoinertial turbulence (EIT) in Taylor-Couette flows of viscoelastic polymer solutions, caused by merging and splitting of base Taylor vortices when crossed by elastic axial waves. Vortex merging and splitting are random in nature and increase in frequency with Reynolds number. When superimposed on a RSW flow state, they cause abrupt changes in the axial spatial wavelength, leading to the transition from a RSW to the EIT state. MST is thus identified as an inertial feature solely triggered by elasticity and independent of any shear-thinning behavior.