Optimal slip velocities of micro-swimmers with arbitrary axisymmetric shapes

Guo, Hanliang; Zhu, Hai; Liu, Ruowen; Bonnet, Marc; Veerapaneni, Shravan

doi:10.1017/jfm.2020.969

Cited by 24 publications

(27 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The optimal unconstrained prolate spheroidal microswimmer with a 2 : 1 aspect ratio has an efficiency ≈ 69 %, about twice as high as the spherical microswimmer as shown in figure 2(a). This roughly two-fold increase in efficiency is also observed in the optimal time-independent microswimmers (Guo et al 2021). The optimal ciliary motion is very close to that of the spherical swimmer (figure 2b,c), while the mean slip velocity of the Eulerian points are between the optimal time-independent slip velocity of the same shape and those of a spherical swimmer, as shown in figure 2(e).…”

Section: Spheroidal Swimmerssupporting

confidence: 64%

“…We showed that the optimal ciliary motions of prolate microswimmer with a 2 : 1 aspect ratio are very close to the ones of spherical microswimmer, while the swimming efficiency can increase two-fold. The mean slip velocity of unconstrained microswimmers also tend to follow the optimal time-independent slip velocity, which can be easily computed using our recent work (Guo et al 2021).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…We use a BIM at every time step. A similar BIM implementation was detailed in our recent work Guo et al (2021) in which we studied the optimisation of time-independent slip profiles. The main procedures are summarised below, with key equations highlighted in boxes.…”

Section: Numerical Algorithm For Solving the Forward Problemmentioning

confidence: 99%

“…The envelope model has been extensively applied to study the locomotion of both single and multiple swimmers (e.g. see Lighthill 1952;Blake 1971;Ishikawa, Simmonds & Pedley 2006;Ishikawa & Pedley 2008;Michelin & Lauga 2010;Vilfan 2012;Brumley et al 2015;Elgeti, Winkler & Gompper 2015;Guo et al 2021;Nasouri, Vilfan & Golestanian 2021), as well as the nutrient uptake of microswimmers (e.g. Magar, Goto & Pedley 2003;Magar & Pedley 2005;Michelin & Lauga 2011.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optimal ciliary locomotion of axisymmetric microswimmers

et al. 2021

Self Cite

View full text Add to dashboard Cite

Many biological microswimmers locomote by periodically beating the densely packed cilia on their cell surface in a wave-like fashion. While the swimming mechanisms of ciliated microswimmers have been extensively studied both from the analytical and the numerical point of view, optimisation of the ciliary motion of microswimmers has received limited attention, especially for non-spherical shapes. In this paper, using an envelope model for the microswimmer, we numerically optimise the ciliary motion of a ciliate with an arbitrary axisymmetric shape. Forward solutions are found using a fast boundary-integral method, and the efficiency sensitivities are derived using an adjoint-based method. Our results show that a prolate microswimmer with a $2\,{:}\,1$ aspect ratio shares similar optimal ciliary motion as the spherical microswimmer, yet the swimming efficiency can increase two-fold. More interestingly, the optimal ciliary motion of a concave microswimmer can be qualitatively different from that of the spherical microswimmer, and adding a constraint to the cilia length is found to improve, on average, the efficiency for such swimmers.

show abstract

Section: Spheroidal Swimmerssupporting

confidence: 64%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Numerical Algorithm For Solving the Forward Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimal ciliary locomotion of axisymmetric microswimmers

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, using the boundary element method and numerical optimization, Guo et al. (2021) showed on some example shapes that when the swimmer body is not front–aft symmetric, pushers or pullers can be more efficient than neutral swimmers. In this study, we systematically investigate the relation between the stresslet and the shape of nearly spherical optimal swimmers.…”

Section: Introductionmentioning

confidence: 99%

Optimal swimmers can be pullers, pushers or neutral depending on the shape

et al. 2021

View full text Add to dashboard Cite

show abstract

Optimal Navigation in Active Matter

Piro

2024

Springer Theses

View full text Add to dashboard Cite

Motile active matter systems are composed by a collection of agents, each of which extracts energy from the surrounding environment in order to convert it into self-driven motion. At the microscopic scale, however, directed motion is hindered by both the presence of stochastic fluctuations. Living microorganisms therefore had to develop simple yet effective propulsion and steering mechanisms in order to survive.We may turn the question of how these processes work in nature around and ask how they should work in order to perform a task in the theoretically optimal way, an issue which falls under the name of the optimal navigation problem. The first formulation of this problem dates back to the seminal work of E. Zermelo in 1931, in which he addressed the question of how to steer a ship in the presence of an external stationary wind so as to reach the destination in the shortest time.Despite the considerable progress made over the years in this context, however, there are still a number of open challenges. In this thesis, we therefore aim to generalize Zermelo's solution by adding more and more ingredients in the description of the optimal navigation problem for microscopic active particles.First, borrowing theoretical tools from differential geometry, we here show how to extend the analytical solution of this problem to when motion occurs on curved surfaces and in the presence of arbitrary flows. Interestingly, we reveal that it can elegantly be solved by finding the geodesics of an asymmetric metric of general relativity, known as the Randers metric.Then, we study the case in which navigation happens in the presence of strong external forces. In this context, route optimization can be crucial as active particles may encounter trapping regions that would substantially slow-down their progress. Comparing the exploration efficiency of Zermelo's solution with a more trivial strategy in which the active agent always points in the same direction, here we highlight the importance of the optimal path stability, which turns out to be fundamental in the design of the proper navigation strategy depending on the task at hand.We then take it a step further and include a key ingredient in the comprehensive study of optimal navigation in active matter, namely stochastic fluctuations. Although methods already exist to obtain both analytically and numerically the optimal strategies even in the presence of noise, their implementation requires the presence of an external interpreter that * Despite this difference, in the following we will actually not make any distinction between these two terms since their observable behavior -when considered individually-is indistinguishable in a homogeneous environment 32 .

show abstract

Optimal slip velocities of micro-swimmers with arbitrary axisymmetric shapes

Abstract: Abstract

Cited by 24 publications

References 31 publications

Optimal ciliary locomotion of axisymmetric microswimmers

Optimal ciliary locomotion of axisymmetric microswimmers

Optimal swimmers can be pullers, pushers or neutral depending on the shape

Optimal Navigation in Active Matter

Contact Info

Product

Resources

About