We suggest several reciprocal swimming mechanisms that lead to locomotion only in viscoelastic fluids. In the first situation, we consider a three-sphere microswimmer with a difference in oscillation amplitudes for the two arms. In the second situation, we consider a three-sphere microswimmer in which one of the frequencies of the arm motion is twice as large as the other one. In the third situation, we consider a two-sphere microswimmer with a difference in size for the two spheres. In all these three cases, the average velocity is proportional to the imaginary part of the complex shear viscosity of a surrounding viscoelastic medium. We show that it is essential for a micromachine to break its structural symmetry in order to swim in a viscoelastic fluid by performing reciprocal body motions.
Reciprocal microswimmers in a viscoelastic fluid
Note: This paper is part of the Special Topic, Fluid-Structure Interactions: From Engineering to Biomimetic Systems.
Kento Yasuda, Mizuki Kuroda, Shigeyuki Komura; Reciprocal microswimmers in a viscoelastic fluid. Physics of Fluids 1 September 2020; 32 (9): 093102. https://doi.org/10.1063/5.0018540
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