Transport of active particles in an open-wedge channel

Caprini, Lorenzo; Cecconi, Fabio; Marconi, Umberto Marini Bettolo

doi:10.1063/1.5090104

Cited by 28 publications

(18 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A cross-over is observed between these two asymptotes. Indeed, all these characteristic traits of narrow escape problems are manifested even in other types of cavity structures [12,43,59]. Based on a minimal two-dimensional Vicsek model, the escape kinetics from a circular cavity has further been extended for interact-ing active particles [58].…”

Section: Introductionmentioning

confidence: 99%

Escape kinetics of self-propelled particles from a circular cavity

Debnath,

Chaudhury,

Mukherjee

et al. 2021

Preprint

View full text Add to dashboard Cite

We numerically investigate the mean exit time of an inertial active Brownian particle from a circular cavity with single or multiple exit windows. Our simulation results witness distinct escape mechanisms depending upon the relative amplitudes of the thermal length and self-propulsion length compared to the cavity and pore sizes. For exceedingly large self-propulsion lengths, overdamped active particles diffuse on the cavity surface, and rotational dynamics solely governs the exit process. On the other hand, the escape kinetics of a very weakly damped active particle is largely dictated by bouncing effects on the cavity walls irrespective of the amplitude of self-propulsion persistence lengths. We show that the exit rate can be maximized for an optimal self-propulsion persistence length, which depends on the damping strength, self-propulsion velocity, and cavity size. However, the optimal persistence length is insensitive to the opening windows' size, number, and arrangement. Numerical results have been interpreted analytically based on qualitative arguments. The present analysis aims to understand the transport controlling mechanism of active matter in confined structures.

show abstract

Section: Introductionmentioning

confidence: 99%

Escape kinetics of self-propelled particles from a circular cavity

Debnath,

Chaudhury,

Mukherjee

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…[12] gives cos θ s ≃ 0.33, ν 0 ≃ 1.2 s −1 , V ≃ 14.2 µm/s, which results in D ≃ 87 µm 2 /s [14]. The diffusive description of bacterial spreading is extensively used because of its simplicity, which allows, for example, to couple this random dynamics with hydrodynamic flows and with the diffusion of nutrients and other chemicals, or to consider complex geometrical restrictions (for recent applications, see [15][16][17][18]). Also, it is possible to include cell division and death by employing reactiondiffusion equations, as it is common in chemical and environmental engineering to describe the spatiotemporal spreading of bacteria [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Run-and-tumble bacteria slowly approaching the diffusive regime

Villa-Torrealba,

Raby,

de Castro

et al. 2020

Preprint

View full text Add to dashboard Cite

The run-and-tumble (RT) dynamics followed by bacterial swimmers gives rise first to a ballistic motion due to their persistence, and later, through consecutive tumbles, to a diffusive process.Here we investigate how long it takes for a dilute swimmer suspension to reach the diffusive regime as well as what is the amplitude of the deviations from the diffusive dynamics. A linear time dependence of the mean-squared displacement (MSD) is insufficient to characterize diffusion and thus we also focus on the excess kurtosis of the displacement distribution. Four swimming strategies are considered: (i) the conventional RT model with complete reorientation after tumbling, (ii) the case of partial reorientation, characterized by a distribution of tumbling angles, (iii) a run-andreverse model with rotational diffusion, and (iv) a RT particle where the tumbling rate depends on the stochastic concentration of an internal protein. By analyzing the associated kinetic equations for the probability density function and simulating the models, we find that for models (ii), (iii), and (iv) the relaxation to diffusion can take much longer than the mean time between tumble events, evidencing the existence of large tails in the particle displacements. Moreover, the excess kurtosis can assume large positive values. In model (ii) it is possible for some distributions of tumbling angles that the MSD reaches a linear time dependence but, still, the dynamics remains non-Gaussian for long times. This is also the case in model (iii) for small rotational diffusivity. For all models, the long-time diffusion coefficients are also obtained. The theoretical approach, which relies on eigenvalue and angular Fourier expansions of the van Hove function, is in excellent agreement with the simulations.

show abstract

“…The dynamics of SPP in complex and nonhomogeneous environments constitute a central issue for its great biological interest. Indeed, in Nature, microswimmers or bacteria, when encounter soft or solid obstacles [22] or even hard walls [23], accumulate in front of them producing interesting patterns [24][25][26][27][28]. Morover, the swimming in porous soil [29], blood flow [30] or biological tissues [31] constitute other contexts of investigation.…”

Section: Introductionmentioning

confidence: 99%

Diffusion properties of self-propelled particles in cellular flows

Caprini¹,

Cecconi²,

Puglisi³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

We study the dynamics of a self-propelled particle advected by a steady laminar flow. The persistent motion of the self-propelled particle is described by an active Ornstein-Uhlenbeck process. We focus on the diffusivity properties of the particle as a function of persistence time and freediffusion coefficient, revealing non-monotonic behaviors, with the occurrence of a minimum and steep growth in the regime of large persistence time. In the latter limit, we obtain an analytical prediction for the scaling of the diffusion coefficient with the parameters of the active force. Our study sheds light on the effect of an inhomogeneous environment on the diffusion of active particles, such as living microorganisms and motile phytoplankton in fluids.

show abstract

Transport of active particles in an open-wedge channel

Cited by 28 publications

References 63 publications

Escape kinetics of self-propelled particles from a circular cavity

Escape kinetics of self-propelled particles from a circular cavity

Run-and-tumble bacteria slowly approaching the diffusive regime

Diffusion properties of self-propelled particles in cellular flows

Contact Info

Product

Resources

About