Cilia beating patterns are not hydrodynamically optimal

Abstract

We examine the hydrodynamic performance of two cilia beating patterns reconstructed from experimental data. In their respective natural systems, the two beating patterns correspond to: (A) pumping-specialized cilia, and (B) swimming-specialized cilia. We compare the performance of these two cilia beating patterns as a function of the metachronal coordination in the context of two model systems: the swimming of a ciliated cylinder and the fluid pumping by a ciliated carpet. Three performance measures are used for this comparison: (i) average swimming speed/pumping flow rate; (ii) maximum internal moments generated by the cilia; and (iii) swimming/pumping efficiencies. We found that, in both models, pattern (B) outperforms pattern (A) in almost all three measures, including hydrodynamic efficiency. These results challenge the notion that hydrodynamic efficiency dictates the cilia beating kinematics, and suggest that other biological functions and constraints play a role in explaining the wide variety of cilia beating patterns observed in biological systems.

15 pages, 8 figures

References in corpus (13)

• The hydrodynamics of swimming microorganisms
• Propulsion in a viscoelastic fluid
• Hydrodynamic flow patterns and synchronization of beating cilia
• Spontaneous creation of macroscopic flow and metachronal waves in an array of cilia
• Finding the ciliary beating pattern with optimal efficiency
• Undulatory swimming in viscoelastic fluids
• Locomotion of helical bodies in viscoelastic fluids: enhanced swimming at large helical amplitudes
• Optimal Swimming at low Reynolds numbers
• Efficiency optimization and symmetry-breaking in a model of ciliary locomotion
• Mixing and transport by ciliary carpets: a numerical study
• Kinematics of the most efficient cilium
• The optimal elastic flagellum
• Microfluidic propulsion by the metachronal beating of magnetic artificial cilia: a numerical analysis

Cited by in corpus (7)

• Bistability in the synchronization of actuated microfilaments
• Flagellar swimmers oscillate between pusher- and puller-type swimming
• Transport efficiency of metachronal waves in 3d cilia arrays immersed in a two-phase flow
• A regularised singularity approach to phoretic problems
• Evaluating efficiency and robustness in cilia design
• Optimal Ciliary Locomotion of Axisymmetric Microswimmers
• Statistical topology of the streamlines of a two-dimensional flow