Trapping of Swimming Microorganisms at Lower Surfaces by Increasing Buoyancy

Jung, Ilyong; Guevorkian, Karine; Valles, James M.

doi:10.1103/physrevlett.113.218101

Cited by 6 publications

(6 citation statements)

References 40 publications

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“…In realistic settings non-buoyant swimmers will naturally interact with bounding surfaces. Their impact has already been studied in several works [36][37][38][39][40][41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Collective dynamics in a monolayer of squirmers confined to a boundary by gravity

2019

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We present a hydrodynamic study of a monolayer of squirmer model microswimmers confined to a boundary by strong gravity using the simulation method of multi-particle collision dynamics. The squirmers interact with each other via their self-generated hydrodynamic flow fields and thereby form a variety of fascinating dynamic states when density and squirmer type are varied. Weak pushers, neutral squirmers, and pullers have an upright orientation. With their flow fields they push neighbors away and thereby form a hydrodynamic Wigner fluid at lower densities. Furthermore, states of fluctuating chains and trimers, of kissing, and at large densities a global cluster exist. Finally, pushers at all densities can tilt against the wall normal and their in-plane velocities align to show swarming. It turns into chaotic swarming for strong pushers at high densities. We characterize all these states quantitatively.

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“…In realistic settings non-buoyant swimmers will naturally interact with bounding surfaces. Their impact has already been studied in several works [36][37][38][39][40][41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Collective dynamics in a monolayer of squirmers confined to a boundary by gravity

2019

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“…of Eq. ( 12) yields ∂ t0 p(θ, t * |θ 0 , t 0 ) = −L + (θ 0 )p(θ, t * |θ 0 , t 0 ) (14) with p(θ, t * |θ 0 , t 0 ) = 2π 0 dφ 0 2π 0 dφP (θ, φ, t * |θ 0 , φ 0 , t 0 ) and L + (θ 0 ) = Ω HI (θ 0 )∂ θ0 + D r (∂ 2 θ0 + cot ∂ θ0 ) (see main text). Finally, taking the integral π θ * .…”

Section: Supplemental Materials 1 Adjoint Smoluchowski Equationmentioning

confidence: 99%

“…To develop an understanding for the accumulation and the dynamics of microorganisms near walls, several important aspects have been investigated recently: swimmer-wall hydrodynamic interactions [7][8][9][10], thermal and intrinsic noise [7,11], cilia-and flagella-wall interactions [12], bacterial tumbling [13], and buoyancy [14]. Whether stochastic motion or swimmer-wall hydrodynamic interactions determine the reorientation of microswimmers at a surface and how they both influence the bacterial distribution between parallel plates has been discussed controversially [7,8,11].…”

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confidence: 99%

Detention times of microswimmers close to surfaces: Influence of hydrodynamic interactions and noise

Schaar,

Zöttl,

Stark

2014

Preprint

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After colliding with a surface, microswimmers reside there during the detention time. They accumulate and may form complex structures such as biofilms. We introduce a general framework to calculate the distribution of detention times using the method of first-passage times and study how rotational noise and hydrodynamic interactions influence the escape from a surface. We compare generic swimmer models to the simple active Brownian particle. While the respective detention times of source dipoles are smaller, the ones of pullers are larger by up to several orders of magnitude, and pushers show both trends. We apply our results to the more realistic squirmer model, for which we use lubrication theory, and validate them by simulations with multi-particle collision dynamics.

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“…Studying microswimmers under gravity is important because often they are not neutrally buoyant [24,25,26,27]. In such a setting non-equilibrium sedimentation has been observed [24,28,29] accompanied by polar order along the vertical [30] and convection [31]. Numerical hydrodynamic studies also discovered two-dimensional Wigner fluids and swarming under strong gravity [32], as well as fluid pumps in a parabolic potential [33].…”

Section: Introductionmentioning

confidence: 99%

Emergent collective dynamics of bottom-heavy squirmers under gravity

Rühle¹,

Stark²

2020

Preprint

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We present the results of hydrodynamic simulations using the method of multi-particle collision dynamics for a system of squirmer microswimmers moving under the influence of gravity at low Reynolds numbers. In addition, the squirmers are bottom-heavy so that they experience a torque which aligns them along the vertical. The squirmers interact hydrodynamically by the flow fields of a stokeslet and rotlet, which are initiated by the acting gravitational force and torque, respectively, and by their own flow fields. By varying the ratio of swimming to bulk sedimentation velocity and the torque, we determine state diagrams for the emergent collective dynamics of neutral squirmers as well as strong pushers and pullers. For low swimming velocity and torque we observe conventional sedimentation, while the sedimentation profile becomes inverted when their values are increased. For neutral squirmers we discover convective rolls of circulating squirmers between both sedimentation states, which sit at the bottom of the system and are fed by plumes made of collectively sinking squirmers. At larger torques porous clusters occur that spawn single squirmers. The two latter states can also occur transiently starting from a uniform squirmer distribution and then disappear in the long-time limit. For strong pushers and pullers only weak plume formation is observed.

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Trapping of Swimming Microorganisms at Lower Surfaces by Increasing Buoyancy

Cited by 6 publications

References 40 publications

Collective dynamics in a monolayer of squirmers confined to a boundary by gravity

Collective dynamics in a monolayer of squirmers confined to a boundary by gravity

Detention times of microswimmers close to surfaces: Influence of hydrodynamic interactions and noise

Emergent collective dynamics of bottom-heavy squirmers under gravity

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