On the dynamics of vortex-wall interaction in low viscosity shear thinning fluids

Olsthoorn, Jason; Stastna, Marek; Steinmoeller, Derek

doi:10.1063/1.4857675

Cited by 8 publications

(6 citation statements)

References 20 publications

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“…At lower Reynolds number, drag coefficients show a stronger dependence on Carreau number in shear-thinning fluids. Olsthoorn, Stastna & Steinmoeller (2014) observed that the interaction of the shear layer with the boundary wall yielded higher levels of kinetic energy in a shear-thinning fluid compared with a Newtonian fluid. They also obtained slower decay of enstrophy owing to smaller dissipation in the shear-thinning fluids.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of flow of a shear-thinning Carreau fluid over a transversely oscillating cylinder

et al. 2021

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of flow of a shear-thinning Carreau fluid over a transversely oscillating cylinder

et al. 2021

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“…Olsthoorn et al [10] studied numerically the vortex dynamics in a non-Newtonian low viscosity fluid following Carreau rheological model. The steadystate mixed convection of Bingham fluids in a cylindrical enclosure with a heated rotating top cover has been numerically analyzed by Turan et al [11].…”

Section: Introductionmentioning

confidence: 99%

Flow patterns of non-Newtonian nanofluid flow in cylindrical enclosure with rotating endwall: Effects of nanoparticles concentration

et al. 2021

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In this paper, a numerical study on the flow structure of non-Newtonian nanofluid in cylindrical enclosure with rotating end wall. The considered nanofluid, MWCNT-water, exhibits a strong power-law shear-thinning behavior with the increase in nanoparticles loading. The main focus in this study is the effect of nanoparticles concentration on the vortex breakdown phenomenon. The simulation results showed that adding a small amount of nanoparticle eliminate the vortex breakdown which is considered as a positive in mixing process. However, the increase in nanoparticles concentration as well as the enclosure aspect ratio promotes the apparition of secondary recirculation zone and stagnation zone.

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“…A shear-thinning fluid typically exhibits viscosity plateaus at both zero-shear-rate (η 0 ) and infinite-shear-rate (η ∞ ). The Carreau-Yasuda model, which captures these plateaus, is thus better suited for characterization of these polymer solutions than the power-law model 2 [11]. Depending on the shear rates, vortex ring can experience two distinctive viscosity variation, (1) power-law variation, and (2) a constant viscosity corresponding to the viscosity plateaus.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of vortex ring evolution in polymer solution

Hegde,

Sreenivas

2019

Preprint

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We have conducted experiments on the effect of polymer solutions on the formation and propagation of vortex rings. We study this effect in aqueous solution of hydrolyzed polyacrylamide (PAMH) at different concentrations. Addition of PAMH imparts shear-rate dependent viscosity and elasticity to the solvent. With increasing concentration of PAMH both the zero-shear-rate viscosity (η 0 ) and the infinite-shear-rate viscosity (η ∞ ) increase. The relaxation time also increase with the increase in concentration. We generate vortex rings using a piston-cylinder mechanism in a glass tank and measure vortex ring properties such as ring position, ring circulation, enstrophy, kinetic energy and peak vorticity using particle image velocimetry (PIV). Experiments are conducted by (1) matching impulse, and (2) matching Reynolds number. We show that, at constant impulse, vortex ring properties in PAMH solution deviate from that in Newtonian water. As the concentration of the PAMH solution increases, so too does the deviation from water. We further perform experiments in water by matching the limiting Reynolds numbers of the PAMH solution corresponding to both η 0 and η ∞ . We find that while the circulation of PAMH solutions lie between the circulation curves of the two extreme Reynolds number matched water experiments for an extended period of time, the enstrophy and peak vorticity do not. We attribute this behaviour to the modification of vorticity distribution within the core of vortex rings in PAMH solutions. We also study the effect of polymer solutions on the formation number. We find that the formation number remains the same even in polymer solutions. We also demonstrate, using planar laser induced fluorescence (PLIF), the phenomenon of ring reversal. Once the vortex ring stops, it begins to unwind and retract by translating and rotating in the opposite direction. We attribute this behaviour of ring reversal to the elastic properties of polymer solutions.

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On the dynamics of vortex-wall interaction in low viscosity shear thinning fluids

Cited by 8 publications

References 20 publications

Numerical simulation of flow of a shear-thinning Carreau fluid over a transversely oscillating cylinder

Numerical simulation of flow of a shear-thinning Carreau fluid over a transversely oscillating cylinder

Flow patterns of non-Newtonian nanofluid flow in cylindrical enclosure with rotating endwall: Effects of nanoparticles concentration

Experimental investigation of vortex ring evolution in polymer solution

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