Experimental study of low inertia vortex rings in shear-thinning fluids
Author(s) -
Omar Bentata,
Dominique Anne-Archard,
Pierre Brancher
Publication year - 2018
Publication title -
physics of fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.188
H-Index - 180
eISSN - 1089-7666
pISSN - 1070-6631
DOI - 10.1063/1.5048841
Subject(s) - physics , mechanics , reynolds number , shear thinning , vortex ring , vortex , particle image velocimetry , non newtonian fluid , classical mechanics , newtonian fluid , viscosity , turbulence , thermodynamics
The present work investigates experimentally the dynamics of vortex rings in shear-thinning fluids at low generalized Reynolds numbers, with a focus on the range from 300 down to 30. The experimental apparatus consists of a vertical cylinder-piston system with the lower part immersed in a tank filled with the liquid. Particle image velocimetry is used to analyze the influence of the non-Newtonian nature of the fluid on the generation, propagation, and eventual dissipation of vortex rings. The results show that shear-thinning controls the generation phase, whereas the vortex ring subsequent evolution is independent of the power-law index. In particular, it is found that the final dissipation stage is characterized by a flow dynamics which tends ultimately to a regime at a constant viscosity corresponding to the Newtonian plateau. This reveals the role of the Carreau number and of the Reynolds number based on this specific viscosity as relevant control parameters for this last stage.
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