Slender phoretic theory of chemically active filaments

Katsamba, Panayiota; Michelin, Sébastien; Montenegro‐Johnson, Thomas D.

doi:10.1017/jfm.2020.410

Cited by 15 publications

(33 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We recovered the intriguing recent finding of Katsamba et al. (2020) that circumferential variations in the concentration field can lead to circumferential slip. This is not seen for simpler geometries.…”

Section: Discussionsupporting

confidence: 87%

“…We note that, recently, a systematic and rigorous derivation of SBT for a chemically active filament was published by Katsamba, Michelin & Montenegro-Johnson (2020), who work from the alternative basis provided by Koens & Lauga (2018). One advantage of working from that basis is that it facilitates consideration of circumferential variation of the surface stress.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, Katsamba et al. (2020) are able to (numerically) calculate particle velocities in the framework of SBT; in that sense, their formulation of SBT is complete. Here, we restrict our attention to calculation of the concentration field.…”

Section: Resultsmentioning

confidence: 99%

“…Additionally, we make no pretence to the level of formal rigor and systematic mathematical development provided in Katsamba et al. (2020). However, our brief treatment may provide an accessible point of entry into SBT for some readers.…”

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Phoretic self-propulsion of helical active particles

Poehnl

Uspal

2021

J. Fluid Mech.

View full text Add to dashboard Cite

Chemically active colloids self-propel by catalysing the decomposition of molecular ‘fuel’ available in the surrounding solution. If the various molecular species involved in the reaction have distinct interactions with the colloid surface, and if the colloid has some intrinsic asymmetry in its surface chemistry or geometry, there will be phoretic flows in an interfacial layer surrounding the particle, leading to directed motion. Most studies of chemically active colloids have focused on spherical, axisymmetric ‘Janus’ particles, which (in the bulk, and in absence of fluctuations) simply move in a straight line. For particles with a complex (non-spherical and non-axisymmetric) geometry, the dynamics can be much richer. Here, we consider chemically active helices. Via numerical calculations and slender body theory, we study how the translational and rotational velocities of the particle depend on geometry and the distribution of catalytic activity over the particle surface. We confirm the recent finding of Katsamba et al. (J. Fluid Mech., vol. 898, 2020, p. A24) that both tangential and circumferential concentration gradients contribute to the particle velocity. The relative importance of these contributions has a strong impact on the motion of the particle. We show that, by a judicious choice of the particle design parameters, one can suppress components of angular velocity that are perpendicular to the screw axis, or even select for purely ‘sideways’ translation of the helix.

show abstract

Section: Discussionsupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Phoretic self-propulsion of helical active particles

Poehnl

Uspal

2021

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…Finally, although the focus of the paper is SBT for the Stokes equations, there are similar SBTs in use in other areas. 22,23 This includes the Laplace equation, [24][25][26] which presents a simpler setting for demonstrating our methods. We include an analogous analysis of the Laplace problem in Appendix C.…”

Section: Introductionmentioning

confidence: 99%

Accuracy of slender body theory in approximating force exerted by thin fiber on viscous fluid

Mori

Ohm

2021

Stud Appl Math

View full text Add to dashboard Cite

We consider the mapping properties of the integral operator arising in nonlocal slender body theory (SBT) for the model geometry of a straight, periodic filament. It is well known that the classical singular SBT integral operator suffers from high wavenumber instabilities, making it unsuitable for approximating the slender body inverse problem, where the fiber velocity is prescribed and the integral operator must be inverted to find the force density along the fiber. Regularizations of the integral operator must therefore be used instead. Here, we consider two regularization methods: spectral truncation and the -regularization of Tornberg and Shelley (2004). We compare the mapping properties of these approximations to the underlying partial differential equation (PDE) solution, which for the inverse problem is simply the Stokes Dirichlet problem with data constrained to be constant on cross sections. For the straight-but-periodic fiber with constant radius > 0, we explicitly calculate the spectrum of the operator mapping fiber velocity to force for both the PDE and the approximations. We prove that the spectrum of the original SBT operator agrees closely with the PDE operator at low wavenumbers but differs at high frequencies, allowing us to define a truncated approximation with a wavenumber cutoff

show abstract