Locomotion of a microorganism in weakly viscoelastic liquids

Corato, Marco De; Greco, Francesco; Maffettone, Pier Luca

doi:10.1103/physreve.92.053008

Cited by 47 publications

(73 citation statements)

References 33 publications

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“…We remark that various types of non-Newtonian rheology (viscoelasticity and shear-thinning rheology) can affect the power dissipation of pushers vs. pullers in different manners. The viscoelastic stress was shown to increase (decrease) the power dissipation for a pusher (puller) [43], however the shear-thinning rheology studied here reduces the power dissipation of a pusher and a puller indifferently as shown in Fig. (1) and by Eq.…”

Section: Power Dissipationmentioning

confidence: 68%

“…We also remark that the non-Newtonian correction to efficiency is even in α as shown in Eq. (23), which means that the shear-thinning rheology has exactly the same effect on the swimming efficiency of a pusher and a puller, again in contrast to the influence of viscoelasticity [43].…”

Section: Swimming Efficiencymentioning

confidence: 97%

“…The non-Newtonian problem can be solved perturbatively to obtain the detailed flow surrounding the squirmer order by order. We instead bypass these detailed calculations via the reciprocal theorem [23,[41][42][43] to calculate the power dissipation and the swimming efficiency of a squirmer in a shear-thinning fluid.…”

Section: Asymptotic Analysesmentioning

confidence: 99%

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Swimming efficiency in a shear-thinning fluid

2017

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Micro-organisms expend energy moving through complex media. While propulsion speed is an important property of locomotion, efficiency is another factor that may determine the swimming gait adopted by a micro-organism in order to locomote in an energetically favorable manner. The efficiency of swimming in a Newtonian fluid is well characterized for different biological and artificial swimmers. However, these swimmers often encounter biological fluids displaying shear-thinning viscosities. Little is known about how this nonlinear rheology influences the efficiency of locomotion. Does the shear-thinning rheology render swimming more efficient or less? How does the swimming efficiency depend on the propulsion mechanism of a swimmer and rheological properties of the surrounding shear-thinning fluid? In this work, we address these fundamental questions on the efficiency of locomotion in a shear-thinning fluid by considering the squirmer model as a general locomotion model to represent different types of swimmers. Our analysis reveals how the choice of surface velocity distribution on a squirmer may reduce or enhance the swimming efficiency. We determine optimal shear rates at which the swimming efficiency can be substantially enhanced compared with the Newtonian case. The nontrivial variations of swimming efficiency prompt questions on how micro-organisms may tune their swimming gaits to exploit the shear-thinning rheology. The findings also provide insights into how artificial swimmers should be designed to move through complex media efficiently.

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Section: Power Dissipationmentioning

confidence: 68%

Section: Swimming Efficiencymentioning

confidence: 97%

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Swimming efficiency in a shear-thinning fluid

2017

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“…Besides, an active particle (AP) in a viscoelastic fluid represents an example of a random walker in a nonequilibrium thermal bath, being of fundamental relevance for non-equilibrium statistical physics [21]. Despite holding such immense potential, theoretical studies involving the dynamics of self-propelled particles in complex fluids are rather scarce [22][23][24][25][26][27][28][29][30][31]. Experiments dealing with artificial microswimmers in viscoelastic fluids, demonstrate remarkable differences compared to entirely viscous environments [32,33].…”

Section: Introductionmentioning

confidence: 99%

Active particles in geometrically confined viscoelastic fluids

2019

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We experimentally study the dynamics of active particles (APs) in a viscoelastic fluid under various geometrical constraints such as flat walls, spherical obstacles and cylindrical cavities. We observe that the main effect of the confined viscoelastic fluid is to induce an effective repulsion on the APs when moving close to a rigid surface, which depends on the incident angle, the surface curvature and the particle activity. Additionally, the geometrical confinement imposes an asymmetry to their movement, which leads to strong hydrodynamic torques, thus resulting in detention times on the wall surface orders of magnitude shorter than suggested by thermal diffusion. We show that such viscoelasticity-mediated interactions have striking consequences on the behavior of multi-AP systems strongly confined in a circular pore. In particular, these systems exhibit a transition from liquid-like behavior to a highly ordered state upon increasing their activity. A further increase in activity melts the order, thus leading to a re-entrant liquid-like behavior.

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“…For the fixed kinematics of the organism, this result suggests that viscoelasticity reduces the propulsion speed of a small-amplitude sheet compared to its Newtonian value, reaching for large Deborah numbers the limit βU BN . These conclusions were extended to other swimmers [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] or fluids with different rheological properties [53][54][55][56][57][58], and were used as a motivation for experimental studies [59][60][61][62][63][64][65][66][67].…”

Section: Introductionmentioning

confidence: 99%

The mechanism of propulsion of a model microswimmer in a viscoelastic fluid next to a solid boundary

Ives

Morozov

2017

Physics of Fluids

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In this paper we study swimming of a model organism, the so-called Taylor's swimming sheet, in a viscoelastic fluid close to a solid boundary. This situation comprises natural habitats of many swimming microorganisms, and while previous investigations have considered the effects of both swimming next to a boundary and swimming in a viscoelastic fluid, seldom have both effects been considered simultaneously. We re-visit the small wave amplitude result obtained by Elfring and Lauga (Gwynn J. Elfring and Eric Lauga, in Saverio E. Spagnolie, editor, Complex Fluids in Biological Systems, Springer New York, New York, NY, 2015), and give a mechanistic explanation to the decoupling of the effects of viscoelasticity, which tend to slow the sheet, and the presence of the boundary, which tends to speed up the sheet. We also develop a numerical spectral method capable of finding the swimming speed of a waving sheet with an arbitrary amplitude and waveform.We use it to show that the decoupling mentioned above does not hold at finite wave amplitudes and that for some parameters the presence of a boundary can cause the viscoelastic effects to increase the swimming speed of microorganisms.

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Locomotion of a microorganism in weakly viscoelastic liquids

Cited by 47 publications

References 33 publications

Swimming efficiency in a shear-thinning fluid

Swimming efficiency in a shear-thinning fluid

Active particles in geometrically confined viscoelastic fluids

The mechanism of propulsion of a model microswimmer in a viscoelastic fluid next to a solid boundary

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