Shape transition and propulsive force of an elastic rod rotating in a viscous fluid

Abstract

The deformation of thin rods in a viscous liquid is central to the mechanics of motility in cells ranging from \textit{Escherichia coli} to sperm. Here we use experiments and theory to study the shape transition of a flexible rod rotating in a viscous fluid driven either by constant torque or at constant speed. The rod is tilted relative to the rotation axis. At low applied torque, the rod bends gently and generates small propulsive force. At a critical torque, the rotation speed increases abruptly and the rod forms a helical shape with much greater propulsive force. We find good agreement between theory and experiment.

4 pages, 5 figures

References in corpus (5)

• Experimental Investigations of Elastic Tail Propulsion at Low Reynolds Number
• Floppy swimming: Viscous locomotion of actuated elastica
• Propulsion with a Rotating Elastic Nanorod
• Rotational dynamics of a soft filament: wrapping transition and propulsive forces
• Non-equilibrium hydrodynamics of a rotating filament

Cited by in corpus (9)

• The hydrodynamics of swimming microorganisms
• Beating patterns of filaments in viscoelastic fluids
• A general formulation of Bead Models applied to flexible fibers and active filaments at low Reynolds number
• Rotational dynamics of a soft filament: wrapping transition and propulsive forces
• Buckling of a beam extruded into highly viscous fluid
• Maximizing propulsive thrust of a driven filament at low Reynolds number via variable flexibility
• Low-Reynolds-number, bi-flagellated Quincke swimmers with multiple forms of motion
• Jet-driven viscous locomotion of confined thermoresponsive microgels
• Buckled in translation