The European Physical Journal E

, 37:60

Rotational propulsion enabled by inertia


    • Commissariat à l’Energie Atomique
  • On Shun Pak
    • Department of Mechanical and Aerospace EngineeringPrinceton University
  • LaiLai Zhu
    • Linné Flow CenterKTH Mechanics
    • Laboratory of Fluid Mechanics and InstabilitiesEPFL
  • Luca Brandt
    • Linné Flow CenterKTH Mechanics
  • Eric Lauga
    • Department of Applied Mathematics and Theoretical PhysicsUniversity of Cambridge, Center for Mathematical Sciences
Regular Article

DOI: 10.1140/epje/i2014-14060-y

Cite this article as:
Nadal, F., Pak, O.S., Zhu, L. et al. Eur. Phys. J. E (2014) 37: 60. doi:10.1140/epje/i2014-14060-y


The fluid mechanics of small-scale locomotion has recently attracted considerable attention, due to its importance in cell motility and the design of artificial micro-swimmers for biomedical applications. Most studies on the topic consider the ideal limit of zero Reynolds number. In this paper, we investigate a simple propulsion mechanism --an up-down asymmetric dumbbell rotating about its axis of symmetry-- unable to propel in the absence of inertia in a Newtonian fluid. Inertial forces lead to continuous propulsion for all finite values of the Reynolds number. We study computationally its propulsive characteristics as well as analytically in the small-Reynolds-number limit. We also derive the optimal dumbbell geometry. The direction of propulsion enabled by inertia is opposite to that induced by viscoelasticity.

Graphical abstract


Soft Matter: Colloids and Nanoparticles
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© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2014