Propulsion of a two-sphere swimmer

We describe experiments and simulations demonstrating the propulsion of a neutrally-buoyant swimmer that consists of a pair of spheres attached by a spring, immersed in a vibrating fluid. The vibration of the fluid induces relative motion of the spheres which, for sufficiently large amplitudes, can...

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Main Authors: Klotsa, Daphne, Baldwin, Kyle A., Hill, Richard J.A., Bowley, R.M., Swift, Michael R.
Format: Article
Published: American Physical Society 2015
Online Access:https://eprints.nottingham.ac.uk/42076/
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author Klotsa, Daphne
Baldwin, Kyle A.
Hill, Richard J.A.
Bowley, R.M.
Swift, Michael R.
author_facet Klotsa, Daphne
Baldwin, Kyle A.
Hill, Richard J.A.
Bowley, R.M.
Swift, Michael R.
author_sort Klotsa, Daphne
building Nottingham Research Data Repository
collection Online Access
description We describe experiments and simulations demonstrating the propulsion of a neutrally-buoyant swimmer that consists of a pair of spheres attached by a spring, immersed in a vibrating fluid. The vibration of the fluid induces relative motion of the spheres which, for sufficiently large amplitudes, can lead to motion of the center of mass of the two spheres. We find that the swimming speed obtained from both experiment and simulation agree and collapse onto a single curve if plotted as a function of the streaming Reynolds number, suggesting that the propulsion is related to streaming flows. There appears to be a critical onset value of the streaming Reynolds number for swimming to occur. We observe a change in the streaming flows as the Reynolds number increases, from that generated by two independent oscillating spheres to a collective flow pattern around the swimmer as a whole. The mechanism for swimming is traced to a strengthening of a jet of fluid in the wake of the swimmer.
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spelling nottingham-420762020-05-04T17:27:05Z https://eprints.nottingham.ac.uk/42076/ Propulsion of a two-sphere swimmer Klotsa, Daphne Baldwin, Kyle A. Hill, Richard J.A. Bowley, R.M. Swift, Michael R. We describe experiments and simulations demonstrating the propulsion of a neutrally-buoyant swimmer that consists of a pair of spheres attached by a spring, immersed in a vibrating fluid. The vibration of the fluid induces relative motion of the spheres which, for sufficiently large amplitudes, can lead to motion of the center of mass of the two spheres. We find that the swimming speed obtained from both experiment and simulation agree and collapse onto a single curve if plotted as a function of the streaming Reynolds number, suggesting that the propulsion is related to streaming flows. There appears to be a critical onset value of the streaming Reynolds number for swimming to occur. We observe a change in the streaming flows as the Reynolds number increases, from that generated by two independent oscillating spheres to a collective flow pattern around the swimmer as a whole. The mechanism for swimming is traced to a strengthening of a jet of fluid in the wake of the swimmer. American Physical Society 2015-12-11 Article PeerReviewed Klotsa, Daphne, Baldwin, Kyle A., Hill, Richard J.A., Bowley, R.M. and Swift, Michael R. (2015) Propulsion of a two-sphere swimmer. Physical Review Letters, 115 (24). 248102/1-248102/5. ISSN 1079-7114 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.248102 doi:10.1103/PhysRevLett.115.248102 doi:10.1103/PhysRevLett.115.248102
spellingShingle Klotsa, Daphne
Baldwin, Kyle A.
Hill, Richard J.A.
Bowley, R.M.
Swift, Michael R.
Propulsion of a two-sphere swimmer
title Propulsion of a two-sphere swimmer
title_full Propulsion of a two-sphere swimmer
title_fullStr Propulsion of a two-sphere swimmer
title_full_unstemmed Propulsion of a two-sphere swimmer
title_short Propulsion of a two-sphere swimmer
title_sort propulsion of a two-sphere swimmer
url https://eprints.nottingham.ac.uk/42076/
https://eprints.nottingham.ac.uk/42076/
https://eprints.nottingham.ac.uk/42076/