Front-back asymmetry controls the impact of viscoelasticity on helical swimming

Angeles, Verónica; Godínez, F. A.; Puente-Velázquez, J. Amadeus; Méndez, Rodrigo Romero; Lauga, Eric; Zenit, Roberto

doi:10.1103/physrevfluids.6.043102

Cited by 12 publications

(20 citation statements)

References 24 publications

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“…A direct comparison between our swimming speed results and those of Zenit and coworkers is not possible because not only the details of the swimmer geometry is different (head diameter, tail thickness, total length of the swimmer, proportion of the tail length to that of the head length) from our swimmers, but also the Boger fluids have a slightly different viscosity ratios ( and 1 (Angeles et al. 2021 a ) or 0.95 (Godínez et al. 2015)).…”

Section: Resultsmentioning

confidence: 69%

“…This mechanism is principally related to local viscoelastic effects near the rotating helix and is inherently distinct from what has been shown theoretically for a ‘snowman swimmer’, a dumbbell composed of two spheres of different diameters (Angeles et al. 2021 b ; Pak et al. 2012).…”

Section: Discussionmentioning

confidence: 80%

“…Zenit and coworkers have also studied swimming dynamics of a series of swimmers similar to our 3D-printed swimmers (with a helical tail and a cylindrical head) (Angeles et al. 2021 a ; Godínez et al. 2015).…”

Section: Resultsmentioning

confidence: 99%

“…In a recent paper, Angeles et al. (2021 a ) showed that the swimming dynamics of helical swimmers in viscoelastic fluids depend strongly on the front–back geometrical asymmetry; i.e. the difference between the head and the helix diameter.…”

Section: Discussionmentioning

confidence: 99%

“…effects due to asymmetry between the diameter of the head and the tail of the swimmer) (Angeles et al. 2021 a ). In our paper, the diameters of the head and helix are the same, and therefore snowman-like effects should be minimal.…”

Section: Discussionmentioning

confidence: 99%

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Formation of a strong negative wake behind a helical swimmer in a viscoelastic fluid

Solano

Shoele

et al. 2022

J. Fluid Mech.

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We investigate the effects of helical swimmer shape (i.e. helical pitch angle and tail thickness) on swimming dynamics in a constant viscosity viscoelastic (Boger) fluid via a combination of particle tracking velocimetry, particle image velocimetry and three-dimensional simulations of the finitely extensible nonlinear elastic model with Peterlin approximation (FENE-P). The 3D-printed helical swimmer is actuated in a magnetic field using a custom-built rotating Helmholtz coil. Our results indicate that increasing the swimmer tail thickness and pitch angle enhances the normalized swimming speed (i.e. ratio of swimming speed in the Boger fluid to that of the Newtonian fluid). Strikingly, unlike the Newtonian fluid, the viscoelastic flow around the swimmer is characterized by formation of a front–back flow asymmetry that is characterized by a strong negative wake downstream of the swimmer's body. Evidently, the strength of the negative wake is inversely proportional to the normalized swimming speed. Three-dimensional simulations of the swimmer with the FENE-P model with conditions that match those of experiments, confirm formation of a similar front–back flow asymmetry around the swimmer. Finally, by developing an approximate force balance in the streamwise direction, we show that the contribution of polymer stresses in the interior region of the helix may provide a mechanism for swimming enhancement or diminution in the viscoelastic fluid.

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Section: Resultsmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 80%