Europhys. Lett.
Volume 74, Number 4, May 2006
Page(s) 719 - 725
Section Interdisciplinary physics and related areas of science and technology
Published online 07 April 2006
Europhys. Lett., 74 (4), pp. 719-725 (2006)
DOI: 10.1209/epl/i2006-10017-9

Surmounting barriers: The benefit of hydrodynamic interactions

C. Lutz1, M. Reichert2, H. Stark2, 3 and C. Bechinger1

1  2. Physikalisches Institut, Universität Stuttgart - Pfaffenwaldring 57 D-70550 Stuttgart, Germany
2  Universität Konstanz, Fachbereich Physik - D-78457 Konstanz, Germany
3  Max-Planck Institute for Dynamics and Self-Organization - Bunsenstr. 10 D-37073 Göttingen, Germany

received 10 January 2006; accepted in final form 9 March 2006
published online 7 April 2006

We experimentally and theoretically investigate the collective behavior of three colloidal particles that are driven by a constant force along a toroidal trap. Due to hydrodynamic interactions, a characteristic limit cycle is observed. When we additionally apply a periodic sawtooth potential, we find a novel caterpillar-like motional sequence that is dominated by hydrodynamic interactions and promotes the surmounting of potential barriers by the particles.

82.70.Dd - Colloids.
67.40.Hf - Hydrodynamics in specific geometries, flow in narrow channels.
83.80.Hj - Suspensions, dispersions, pastes, slurries, colloids.

© EDP Sciences 2006