Propulsion and Instability of a Flexible Helical Rod Rotating in a Viscous Fluid
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PhysRevLett.115.168101.pdf
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Author(s)
Da, F.
Grinspun, E.
Khalid Jawed, Mohammad
Khouri, Noor K.
Reis, Pedro Miguel
Date Issued
October 2015
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Jawed, M. K., N. K. Khouri, F. Da, E. Grinspun, and P. M. Reis. "Propulsion and Instability of a Flexible Helical Rod Rotating in a Viscous Fluid." Phys. Rev. Lett. 115, 168101 (October 2015). © 2015 American Physical Society
Version
Final published version
Abstract
We combine experiments with simulations to investigate the fluid-structure interaction of a flexible helical rod rotating in a viscous fluid, under low Reynolds number conditions. Our analysis takes into account the coupling between the geometrically nonlinear behavior of the elastic rod with a nonlocal hydrodynamic model for the fluid loading. We quantify the resulting propulsive force, as well as the buckling instability of the originally helical filament that occurs above a critical rotation velocity. A scaling analysis is performed to rationalize the onset of this instability. A universal phase diagram is constructed to map out the region of successful propulsion and the corresponding boundary of stability is established. Comparing our results with data for flagellated bacteria suggests that this instability may be exploited in nature for physiological purposes.
MIT Department
Massachusetts Institute of Technology. Department of Architecture
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.115.168101
