Setting the pace of microswimmers: when increasing viscosity speeds up self-propulsion

Journal article
(Original article)

Publication Details

Author(s): Pande J, Merchant L, Kruger T, Harting J, Smith AS
Journal: New Journal of Physics
Publication year: 2017
Volume: 19
ISSN: 1367-2630


It has long been known that some microswimmers seem to swim counter-intuitively faster when the viscosity of the surrounding fluid is increased, whereas others slow down. This conflicting dependence of the swimming velocity on the viscosity is poorly understood theoretically. Here we explain that any mechanical microswimmer with an elastic degree of freedom in a simple Newtonian fluid can exhibit both kinds of response to an increase in the fluid viscosity for different viscosity ranges, if the driving is weak. The velocity response is controlled by a single parameter Gamma, the ratio of the relaxation time of the elastic component of the swimmer in the viscous fluid and the swimming stroke period. This defines two velocity-viscosity regimes, which we characterize using the bead-spring microswimmer model and analyzing the different forces acting on the parts of this swimmer. The analytical calculations are supported by lattice-Boltzmann simulations, which accurately reproduce the two velocity regimes for the predicted values of Gamma.

FAU Authors / FAU Editors

Pande, Jayant
Professur für Theoretische Physik
Smith, Ana-Suncana Prof. Dr.
Professur für Theoretische Physik

Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials

External institutions
Forschungszentrum Jülich GmbH (FZJ)
University of Edinburgh

How to cite

Pande, J., Merchant, L., Kruger, T., Harting, J., & Smith, A.-S. (2017). Setting the pace of microswimmers: when increasing viscosity speeds up self-propulsion. New Journal of Physics, 19.

Pande, Jayant, et al. "Setting the pace of microswimmers: when increasing viscosity speeds up self-propulsion." New Journal of Physics 19 (2017).


Last updated on 2018-07-08 at 22:54