Efficiency optimization and symmetry-breaking in a model of ciliary locomotion

By S. Michelin, Eric Lauga. 2010

139 citations recorded by the source corpus.

A variety of swimming microorganisms, called ciliates, exploit the bending of a large number of small and densely packed organelles, termed cilia, in order to propel themselves in a viscous fluid. We consider a spherical envelope model for such ciliary locomotion where the dynamics of the individual cilia are replaced by that of a continuous overlaying surface allowed to deform tangentially to itself. Employing a variational approach, we determine numerically the time-periodic deformation of such surface which leads to low-Reynolds locomotion with minimum rate of energy dissipation (maximum efficiency). Employing both Lagrangian and Eulerian points of views, we show that in the optimal swimming stroke, individual cilia display weak asymmetric beating, but that a significant symmetry-breaking occurs at the organism level, with the whole surface deforming in a wavelike fashion reminiscent of metachronal waves of biological cilia. This wave motion is analyzed using a formal modal decomposition, is found to o...

Subfields: Aerospace Engineering, Condensed Matter Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/49b9b9014c3042db12cb04270e6803e51a4fbcea

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In Aerospace Engineering

In Condensed Matter Physics

In Statistical and Nonlinear Physics

Citations in the corpus

Self-propulsion in viscoelastic fluids: Pushers vs. pullers (2012, background): “The efficiency is defined as the ratio between the rate work needed to pull a sphere of same size in the same fluid at the swimming speed U and the swimming power P of a self-propelled swimmer [51, 52] η = FU P , (12)”
Spherical squirmers: models for swimming micro-organisms (2016, background): “(2.10) at V ienna U niversity L ibrary on O ctober 10, 2016 http://im am at.oxfordjournals.org/ This suggests the possibility of optimization; Michelin & Lauga (2010) have indeed shown that the minimum energy dissipation for a given swimming speed, or equivalently the maximum speed for a given…”
Hydrodynamics of self-propulsion near a boundary: predictions and accuracy of far-field approximations (2012, background): “…Pedley (2006) and Kanevsky, Shelley & Tornberg (2010), hydrodynamically bound states by Drescher et al. (2009), efficiency optimization in ciliary beating by Michelin & Lauga (2010), fluid stirring effects by Lin, Thiffeault, & Childress (2011), and motion in a polymeric fluid by Zhu et al. (2011).”