Hydrodynamic segregation in a bidisperse colloidal suspension in microchannel flow: A theoretical study

Kanehl, Philipp; Stark, Holger

doi:10.1063/1.4921800

Cited by 19 publications

(14 citation statements)

References 78 publications

(105 reference statements)

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“…This reproduces well known effects where solid aggregates move to regions with lower shear rates, reported by [6,7] as well as general shear-induced particle migration, as reported by [36]. However, the number of solid particles is to small to investigate phenomena like de-mixing as observed in [3]. Therefore future investigations will include simulations with more solid particles to analyze these effects more closely.…”

Section: Resultssupporting

confidence: 86%

“…Such continuum models present a good approximation when it comes to general investigations of fluid flow of suspensions on length scales significantly larger than the characteristic particle diameter. However there is no information about the microscopical influence of solid-solid contacts as well as hydro-mechanical fluid-solid interactions which could lead to well-known phenomena like de-mixing [3], particle formation like hydroclusters [4,5] and shear-wall migration [6,7]. To overcome limitations of classical macroscopic continuum formulations, we present a multi-scale modeling approach for fully resolved suspensions.…”

Section: Introductionmentioning

confidence: 99%

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Modelling of Non-Spherical Particles in Dilute Non-Colloidal Suspensions Using SPH

Kijanski¹,

Krach²,

Steeb³

2020

Preprint

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Suspensions and their applications can be found in many engineering, environmental or medical fields. Considering the special field of dilute suspensions, possible applications are cement paste or procedural processes in the production of medication or food. While the homogenized behavior of these applications is well understood, contributions in the field of pore-scale fully resolved numerical simulations with non-spherical particles are rare. Using Smoothed Particle Hydrodynamics as a simulation framework we therefore present a model for Direct Numerical Simulations of single-phase fluid containing non-spherically formed solid aggregates. Notable and discussed model specifications are the surface-coupled fluid-solid interaction forces as well as the contact forces between solid aggregates. Moreover we simulate and analyze the behavior of dilute non-colloidal suspensions of non-spherical solid particles in Newtonian fluids. The focus of this contribution is the numerical model for suspensions and its implementation in SPH. Therefore shown numerical examples present application examples for a first numerical analysis of influence factors in suspension flow. Results show that direct numerical simulations reproduce known phenomena like shear induced migration very well. Moreover the present investigation exemplifies the influence of concentration and form of particles on the flow processes in greater detail.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Modelling of Non-Spherical Particles in Dilute Non-Colloidal Suspensions Using SPH

Kijanski¹,

Krach²,

Steeb³

2020

Preprint

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“…MPCD reliably reproduces analytical results, including the flow field around passive colloids [59], the friction coefficient of a particle approaching a plane wall [63], the active velocity of squirmers [49], as well as the torque acting on them close to walls, where lubrication theory has to be applied [41]. It also simulates correctly segregation and velocity oscillations in dense colloidal suspensions under Poiseuille flow [64,65]. MPCD resolves flow fields on time and length scales large compared to the duration of the streaming step ∆t and the mean free path of the fluid particles, respectively.…”

Section: B Multi-particle Collision Dynamicsmentioning

confidence: 57%

Collective sedimentation of squirmers under gravity

et al. 2017

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Active particles, which interact hydrodynamically, display a remarkable variety of emergent collective phenomena. We use squirmers to model spherical microswimmers and explore the collective behavior of thousands of them under the influence of strong gravity using the method of multi-particle collision dynamics for simulating fluid flow. The sedimentation profile depends on the ratio of swimming to sedimentation velocity as well as on the squirmer type. It shows closely packed squirmer layers at the bottom and a highly dynamic region with exponential density dependence towards the top. The mean vertical orientation of the squirmers strongly depends on height. For swimming velocities larger than the sedimentation velocity, squirmers show strong convection in the exponential region. We quantify the strength of convection and the extent of convection cells by the vertical current density and its current dipole, which are large for neutral squirmers as well as for weak pushers and pullers.

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“…[75][76][77] 84 and a binary colloidal suspension demixing under Poiseuille flow. 85 MPCD uses point particles of mass m 0 as coarse-grained fluid particles. Their dynamics consists of a ballistic streaming and a collision step, which locally conserves momentum.…”

Section: A Multi-particle Collision Dynamicsmentioning

confidence: 99%

Taylor line swimming in microchannels and cubic lattices of obstacles

et al. 2016

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a Microorganisms naturally move in microstructured fluids. Using the simulation method of multi-particle collision dynamics, we study in two dimensions an undulatory Taylor line swimming in a microchannel and in a cubic lattice of obstacles, which represent simple forms of a microstructured environment.In the microchannel the Taylor line swims at an acute angle along a channel wall with a clearly enhanced swimming speed due to hydrodynamic interactions with the bounding wall. While in a dilute obstacle lattice swimming speed is also enhanced, a dense obstacle lattice gives rise to geometric swimming. This new type of swimming is characterized by a drastically increased swimming speed. Since the Taylor line has to fit into the free space of the obstacle lattice, the swimming speed is close to the phase velocity of the bending wave traveling along the Taylor line. While adjusting its swimming motion within the lattice, the Taylor line chooses a specific swimming direction, which we classify by a lattice vector. When plotting the swimming velocity versus the magnitude of the lattice vector, all our data collapse on a single master curve. Finally, we also report more complex trajectories within the obstacle lattice.

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Hydrodynamic segregation in a bidisperse colloidal suspension in microchannel flow: A theoretical study

Cited by 19 publications

References 78 publications

Modelling of Non-Spherical Particles in Dilute Non-Colloidal Suspensions Using SPH

Modelling of Non-Spherical Particles in Dilute Non-Colloidal Suspensions Using SPH

Collective sedimentation of squirmers under gravity

Taylor line swimming in microchannels and cubic lattices of obstacles

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