Propulsive Force Measurements and Flow Behavior of Undulatory Swimmers at Low Reynolds Number

The swimming behavior of the nematode Caenorhabditis elegans is investigated in aqueous solutions of increasing viscosity. Detailed flow dynamics associated with the nematode’s swimming motion as well as propulsive force and power are obtained using particle tracking and velocimetry methods. We find that C. elegans delivers propulsive thrusts on the order of a few nanonewtons. Such findings are supported by values obtained using resistive force theory; the ratio of normal to tangential drag coefficients is estimated to be approximately 1.4. Over the range of solutions investigated here, the flow properties remain largely independent of viscosity. Velocity magnitudes of the flow away from the nematode body decay rapidly within less than a body length and collapse onto a single master curve. Overall, our findings support that C. elegans is an attractive living model to study the coupling between small-scale propulsion and low Reynolds number hydrodynamics. Disciplines Engineering | Mechanical Engineering Comments Suggested Citation: J. Sznitman, X. Shen, R. Sznitman and P.E. Arratia. (2010). "Propulsive force measurements and flow behavior of undulatory swimmers at low Reynolds number." Physics of Fluids 22, 121901. © 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Fluids and may be found at http://dx.doi.org/10.1063/1.3529236. This journal article is available at ScholarlyCommons: http://repository.upenn.edu/meam_papers/264 Propulsive force measurements and flow behavior of undulatory swimmers at low Reynolds number J. Sznitman, X. Shen, R. Sznitman, and P. E. Arratia Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 2128, USA Received 18 June 2010; accepted 30 November 2010; published online 22 December 2010 The swimming behavior of the nematode Caenorhabditis elegans is investigated in aqueous solutions of increasing viscosity. Detailed flow dynamics associated with the nematode’s swimming motion as well as propulsive force and power are obtained using particle tracking and velocimetry methods. We find that C. elegans delivers propulsive thrusts on the order of a few nanonewtons. Such findings are supported by values obtained using resistive force theory; the ratio of normal to tangential drag coefficients is estimated to be approximately 1.4. Over the range of solutions investigated here, the flow properties remain largely independent of viscosity. Velocity magnitudes of the flow away from the nematode body decay rapidly within less than a body length and collapse onto a single master curve. Overall, our findings support that C. elegans is an attractive living model to study the coupling between small-scale propulsion and low Reynolds number hydrodynamics. © 2010 American Institute of Physics. doi:10.1063/1.3529236