Slow parallel motion of cylinders in non-Newtonian media: wall effects and drag coefficient

Unnikrishnan, A.; Chhabra, R.P.

doi:10.1016/0255-2701(90)80008-s

Cited by 14 publications

(6 citation statements)

References 17 publications

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“…Given the difficulty of an unambiguous description of size, shape and orientation of non-spherical particles, this level of accuracy is regarded to be reasonable and adequate for process engineering design calculations. Reynolds number for a Newtonian fluid (qVd s / l) (-) Re PL power law Reynolds number (qV 2 À n d s n / m (-) V terminal falling velocity of a particle (m/s) Table 2 Summary of experimental data in power law fluids Source Particle shape w n R e PL Unnikrishnan and Chhabra (1990) Vertically falling cylinders 0.6-0.95 0.48-0.6 0.01-1.7 Sharma and Chhabra (1991) Cones 0.64-0.80 0.3-0.85 0.01-36 Venumadhav and Chhabra (1994) Cylinders and prisms 0.33-0.98 0.77-0.96 0.1-140 Tripathi et al (1994) Oblates and prolates 0.62-0.93 0.4-1 0.01-100 Borah and Chhabra (2005) Cones 0 shear rate (s À 1 ) k ratio of surface area to projected area (-) l…”

Section: Discussionmentioning

confidence: 99%

Drag on non-spherical particles in power law non-Newtonian media

Rajitha

Chhabra

Sabiri

et al. 2006

International Journal of Mineral Processing

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Section: Discussionmentioning

confidence: 99%

Drag on non-spherical particles in power law non-Newtonian media

Rajitha

Chhabra

Sabiri

et al. 2006

International Journal of Mineral Processing

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“…More recently, vortex shedding characteristics from a circular cylinder in power law fl uids have been studied by Coelho et al (1996) and Pinho (2003a, b, 2004) in the Reynolds number range 50-9000. Finally, while some results on the drag on freely falling non-spherical particles including short cylinders (l/d<∼ 10) in power law fl uids are available in the literature (Machac et al, 2002;Rajitha et al, 2006;Rodrigue et al, 1994;Unnikrishnan and Chhabra, 1990;Venu Madhav and Chhabra, 1994), there are virtually no results available on the cross fl ow of long cylinders. In summary, there is essentially only one numerical study (i.e., Chhabra et al, 2004;Soares et al, 2005) available in which the fl ow of power law fl uids has been examined for three values of the Reynolds number (5, 20 and 40) and for the power law index in the range (0.6 ≤ n ≤ 1.4).…”

Section: Steady Flow Of Power Law Fluids Across a Circular Cylindermentioning

confidence: 99%

Steady Flow of Power Law Fluids across a Circular Cylinder

2006

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gammes de conditions, soit 5 ≤ Re ≤ 40 et 0,6 ≤ n ≤ 2. Le comportement rhéofl uidifi ant (n < 1) du fl uide réduit la taille de la zone de recirculation et accroît également la séparation; d'autre part, les fl uides rhéoépaississants (n > 1) montrent un comportement opposé. En outre, alors que la taille du sillage varie de manière non monotone avec l'indice de loi de puissance, elle ne semble pas infl uencer les valeurs du coeffi cient de traînée. Le coeffi cient de pression de stagnation et le coeffi cient de traînée montrent aussi une dépendance complexe envers l'indice de loi de puissance et le nombre de Reynolds. Les distributions des coeffi cients de pression, de la vorticité et de la viscosité sur la surface du cylindre sont également présentées afi n de mieux comprendre les cinématiques d'écoulement détaillées.

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“…Comparing these experimental result to semiempirical predictions, despite qualitative agreement, the drag coefficient was overestimated by theoretical predictions [43,44]. Comparable studies have also probed wall effects [39,45], different cross sections [46] and interactions between particles [47].…”

Section: Introductionmentioning

confidence: 80%

Empirical resistive-force theory for slender biological filaments in shear-thinning fluids

Riley

Lauga

2017

Phys. Rev. E

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Many cells exploit the bending or rotation of flagellar filaments in order to self-propel in viscous fluids. While appropriate theoretical modelling is available to capture flagella locomotion in simple, Newtonian fluids, formidable computations are required to address theoretically their locomotion in complex, nonlinear fluids, e.g. mucus. Based on experimental measurements for the motion of rigid rods in non-Newtonian fluids and on the classical Carreau fluid model, we propose empirical extensions of the classical Newtonian resistive-force theory to model the waving of slender filaments in non-Newtonian fluids. By assuming the flow near the flagellum to be locally Newtonian, we propose a self-consistent way to estimate the typical shear-rate in the fluid, which we then use to construct correction factors to the Newtonian local drag coefficients. The resulting non-Newtonian resistiveforce theory, while empirical, is consistent with the Newtonian limit, and with the experiments. We then use our models to address waving locomotion in non-Newtonian fluids, and show that the resulting swimming speeds are systematically lowered -a result which we are able to capture asymptotically and to interpret physically. An application of the models to recent experimental results on the locomotion of Caenorhabditis elegans in polymeric solutions shows reasonable agreement and thus captures the main physics of swimming in shear-thinning fluids.

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Slow parallel motion of cylinders in non-Newtonian media: wall effects and drag coefficient

Cited by 14 publications

References 17 publications

Drag on non-spherical particles in power law non-Newtonian media

Drag on non-spherical particles in power law non-Newtonian media

Steady Flow of Power Law Fluids across a Circular Cylinder

Empirical resistive-force theory for slender biological filaments in shear-thinning fluids

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