Vortex merging and splitting: A route to elastoinertial turbulence in Taylor-Couette flow
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Volume
5
Publisher
DOI
10.1103/PhysRevFluids.5.113303
Journal
PHYSICAL REVIEW FLUIDS
Issue
ISSN
2469-990X
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We report experimental evidence 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 (rotating standing waves, RSW). These vortex merging and splitting events are not due to transient behavior, finite aspect ratio, or shear-thinning behavior. They are random in nature and increase in frequency with Re; 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. We thus identify MST as an inertial feature solely triggered by elasticity and independent of any shear-thinning behavior.