Dynamics of a flexible helical filament rotating in a viscous fluid near a rigid boundary
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PhysRevFluids.2.034101.pdf
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Author(s)
Khalid Jawed, Mohammad
Reis, Pedro Miguel
Date Issued
March 2017
Journal
Physical Review Fluids
Publisher
American Physical Society (APS)
Citation
Jawed, M. K. and P. M. Reis. “Dynamics of a Flexible Helical Filament Rotating in a Viscous Fluid Near a Rigid Boundary.” Physical Review Fluids 2, 3 (March 2017): 034101 © 2017 American Physical Society
Version
Final published version
Abstract
We study the effect of a no-slip rigid boundary on the dynamics of a flexible helical filament rotating in a viscous fluid, at low Reynolds number conditions (Stokes limit). This system is taken as a reduced model for the propulsion of uniflagellar bacteria, whose locomotion is known to be modified near solid boundaries. Specifically, we focus on how the propulsive force generated by the filament, as well as its buckling onset, are modified by the presence of a wall. We tackle this problem through numerical simulations that couple the elasticity of the filament, the hydrodynamic loading, and the wall effect. Each of these three ingredients is respectively modeled by the discrete elastic rods method (for a geometrically nonlinear description of the filament), Lighthill's slender body theory (for a nonlocal fluid force model), and the method of images (to emulate the boundary). The simulations are systematically validated by precision experiments on a rescaled macroscopic apparatus. We find that the propulsive force increases near the wall, while the critical rotation frequency for the onset of buckling usually decreases. A systematic parametric study is performed to quantify the dependence of the wall effects on the geometric parameters of the helical filament.
MIT Department
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/PHYSREVFLUIDS.2.034101
