Squirming in a viscous fluid enclosed by a Brinkman medium

Nganguia, Herve; Zhu, Lailai; Palaniappan, D.; Pak, On Shun

doi:10.1103/physreve.101.063105

Cited by 18 publications

(19 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the pusher, relative to the unconfined speed V N , the swimming speed V is reduced to 0.769V N , 0.987V N , and 0.99994V N at Pe= 6, 0.15, and 0.0015, respectively, while for the puller V increases to 1.02V N and 1.0002V N at Pe=0.15 and 0.0015, respectively. Interestingly, the observed decrease in swimming speed for pushers is opposite of the effect of 2D confinement [68] on swimming sheets, and that of spherically symmetric confinement of squirmers propelled by radial deformations [71].…”

Section: Hydrodynamic Modelmentioning

confidence: 82%

“…It remains unclear how swimming in a co-moving pocket of confinement affects swimming speeds, with contradictory results from previous theoretical studies. A model of pocket formation [68] simplified the confinement problem to a two-dimensional waving sheet swimming in a layer of fluid of thickness h confined by a Brinkman medium representing the mucus gel [69], resulting in increased swimming speeds for all h. In contrast, fully three-dimensional analytic models [70,71] of a spherical squirmer in a spherical pocket of fluid confined by another fluid of higher viscosity [70], or a Brinkman medium [71], found that squirmers with prescribed tangential surface velocities slowed down, but those with radial surface velocities sped up.…”

Section: Active Remodeling Of Confinement By H Pylorimentioning

confidence: 99%

See 1 more Smart Citation

Fore-aft clearance controls how three-dimensional confinement affects micropropulsion

Kamarapu¹,

Jabbarzadeh²,

Fu³

2022

Preprint

View full text Add to dashboard Cite

Systems of active particles are often affected by confinement due to nearby boundaries. Recently, there has been interest in the effect of confinement by complex three dimensional geometries, as might occur in structured environments such as porous media, foams, gels, or biological tissues and ducts. The effects of confinement for particles moving along boundaries has been extensively studied, but in three dimensions active particles move not only parallel to boundaries, but also towards or away from boundaries. The consequences of this fore-aft clearance is less well understood. Swimmers that actively remodel their environment create an ideal situation to study the effect of clearance, since they maintain a steady clearance while translating. By numerically studying the locomotion of the bacterium Helicobacter pylori, which de-gels surrounding gastric mucus to make a comoving pocket of fluid around itself, we show that the effect of three-dimensional confinement is controlled by clearance, rather than distance from a parallel boundary. Analytical calculations show that the effect of clearance can be understood in terms of flow structures, such as the generic pusher and puller flows of active particles, indicating that our results should apply to a wide range of confined active particles.

show abstract

Section: Hydrodynamic Modelmentioning

confidence: 82%

Section: Active Remodeling Of Confinement By H Pylorimentioning

confidence: 99%

Fore-aft clearance controls how three-dimensional confinement affects micropropulsion

Kamarapu¹,

Jabbarzadeh²,

Fu³

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…To describe the confinement for active droplets, we use the thin film approximation by Brinkman and others [73,[85][86][87][88][89]. Here we assume that the pressure is constant along the vertical z direction, p(x, y, z) = p(x, y), in Cartesian coordinates, and the flow velocity follows a Poiseuille profile,…”

Section: Squirmer In a Brinkman Medium A Brinkman Equationsmentioning

confidence: 99%

Collective entrainment and confinement amplify transport by schooling micro-swimmers

Jin,

Chen,

Maass

et al. 2021

Preprint

View full text Add to dashboard Cite

Micro-swimmers can serve as cargo carriers that move deep inside complex flow networks. When a school collectively entrains the surrounding fluid, their transport capacity can be enhanced. This effect is quantified with good agreement between experiments with self-propelled droplets and a confined Brinkman squirmer model. The volume of liquid entrained can be much larger than the droplet itself, amplifying the effective cargo capacity over an order of magnitude, even for dilute schools. Hence, biological and engineered swimmers can efficiently transport materials into confined environments.

show abstract

“…On the other hand, at the macro scale, we treat this collection as a bed of porous medium. More recently, Nganguia et al [48] have employed a similar mathematical structure via squirmer model to probe swimming of a H.pylori bacterium which creates and modifies a biological barrier during migration. Here, we assume a similar structure for a suspension containing sufficiently many squirmers such that beyond the individual cellular space, the medium can be treated as an equivalent Brinkman medium [36] so as to produce appreciable changes in the properties of any constituent squirmer.…”

Section: Mathematical Formulationmentioning

confidence: 99%

Effective medium model for a suspension of active swimmers

Dhar,

Burada,

Sekhar

2021

Preprint

View full text Add to dashboard Cite

Several active organisms in nature tend to reside as a community in a viscous fluid medium.We analyze the variation of swimming characteristics of an active swimmer present in a dilute and disperse suspension, modeled as an effective Brinkman medium. This idealized representation of a collection of active swimmers allows one to distinguish the impact of the interior domain available to an individual swimmer as well as the contribution of its neighbours. The Darcy's law along with the analytical solution enable the effective resistivity to be predicted as a function of the volume fraction which is in close agreement with the well known Carman-Kozeny equation. This facilitates the successive analysis of the propulsion speed, power dissipation, and swimming efficiency of the targeted swimmer as a function of the volume fraction which are decisive in nutrient transport and uptake or reproduction in a collective environment. A stress-jump condition is also imposed across a cell to indicate a mean effective force due to the nearby swimmers. At suitable values of this stress-jump coefficient, the relative increase of the migration velocity and swimming efficiency is noticeably higher at an optimum occupancy.

show abstract

Squirming in a viscous fluid enclosed by a Brinkman medium

Cited by 18 publications

References 81 publications

Fore-aft clearance controls how three-dimensional confinement affects micropropulsion

Fore-aft clearance controls how three-dimensional confinement affects micropropulsion

Collective entrainment and confinement amplify transport by schooling micro-swimmers

Effective medium model for a suspension of active swimmers

Contact Info

Product

Resources

About