Pairwise interactions in inertially driven one-dimensional microfluidic crystals

Hood, Kaitlyn; Roper, Marcus

doi:10.1103/physrevfluids.3.094201

Cited by 22 publications

(18 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, we find that all bound particle pairs performing damped oscillations assemble at an axial distance of ∆z/a ≈ 4.1 independent of their initial conditions or the Reynolds number, which we varied between 2 and 20. The value of this axial distance is in good agreement with experimental and theoretical results [28,30,31,54]. The scaling of the lift force with Re (cf.…”

Section: B Two-particle Trajectoriessupporting

confidence: 88%

“…7) indicates that at this equilibrium distance the particle interactions are dominated by a viscous disturbance flow as already mentioned above and in Refs. [29,54]. The shape of this flow does not depend on the Reynolds number, which explains why the equilibrium distance is independent of Re.…”

Section: B Two-particle Trajectoriesmentioning

confidence: 78%

“…In addition to the cross-streamline pairs Hood and Roper [54] also formulated a theory that predicts stable samestreamline pairs. However, in our analysis particles moving on the same side of the channel never form bound states.…”

Section: B Two-particle Trajectoriesmentioning

confidence: 99%

See 2 more Smart Citations

A flowing pair of particles in inertial microfluidics

2019

View full text Add to dashboard Cite

A flowing pair of particles in inertial microfluidics gives important insights into understanding and controlling the collective dynamics of particles like cells or droplets in microfluidic devices. They are applied in medical cell analysis and engineering. We study the dynamics of a pair of solid particles flowing through a rectangular microchannel using lattice Boltzmann simulations. We determine the inertial lift force profiles as a function of the two particle positions, their axial distance, and the Reynolds number. Generally, the profiles strongly differ between particles leading and lagging in flow and the lift forces are enhanced due to the presence of a second particle. At small axial distances, they are determined by viscous forces, while inertial forces dominate at large separations. Depending on the initial conditions, the two-particle lift forces in combination with the Poiseuille flow give rise to three types of unbound particle trajectories, called moving-apart, passing, and swapping, and one type of bound trajectories, where the particles perform damped oscillations. The damping rate scales with Reynolds number squared, since inertial forces are responsible for driving the particles to their steady-state positions.arXiv:1711.01148v2 [physics.flu-dyn]

show abstract

Section: B Two-particle Trajectoriessupporting

confidence: 88%

Section: B Two-particle Trajectoriesmentioning

confidence: 78%

See 1 more Smart Citation

A flowing pair of particles in inertial microfluidics

2019

View full text Add to dashboard Cite

show abstract

“…The second particle then follows the streamlines created by the first particle and spirals in damped oscillations toward its equilibrium position [25]. This idea is also confirmed by analytical calculations [26]. As shown in ref.…”

Section: Staggered and Linear Multi-particle Trainssupporting

confidence: 70%

Particle pairs and trains in inertial microfluidics

Schaaf

Stark

2020

Eur. Phys. J. E

View full text Add to dashboard Cite

Staggered and linear multi-particle trains constitute characteristic structures in inertial microfluidics. Using lattice-Boltzmann simulations, we investigate their properties and stability, when flowing through microfluidic channels. We confirm the stability of cross-streamline pairs by showing how they contract or expand to their equilibrium axial distance. In contrast, same-streamline pairs quickly expand to a characteristic separation but even at long times slowly drift apart. We reproduce the distribution of particle distances with its characteristic peak as measured in experiments. Staggered multi-particle trains initialized with an axial particle spacing larger than the equilibrium distance contract non-uniformly due to collective drag reduction. Linear particle trains, similar to pairs, rapidly expand toward a value about twice the equilibrium distance of staggered trains and then very slowly drift apart non-uniformly. Again, we reproduce the statistics of particle distances and the characteristic peak observed in experiments. Finally, we thoroughly analyze the damped displacement pulse traveling as a microfluidic phonon through a staggered train and show how a defect strongly damps its propagation.

show abstract

“…The origin of particle alignment seems to result from a fa- vorable vortex connection between consecutive particles as illustrated in figure 5. The vortex generated behind the front particle interacts with the vortex induced in front of the lagging particle, minimizing by that the fluctuating kinetic energy (in a similar way to particles interacting in oscillatory fluid flows [36], as discussed by [37]). However the vortex connection does not seem to occur when the train exceeds a certain number of aligned particles.…”

Section: Discussion On the Destabilizing Mechanismmentioning

confidence: 99%

Conditional stability of particle alignment in finite-Reynolds-number channel flow

et al. 2018

View full text Add to dashboard Cite

Finite-size neutrally buoyant particles in a channel flow are known to accumulate at specific equilibrium positions or spots in the channel cross-section if the flow inertia is finite at the particle scale. Experiments in different conduit geometries have shown that while reaching equilibrium locations, particles tend also to align regularly in the streamwise direction. In this paper, the Force Coupling Method was used to numerically investigate the inertia-induced particle alignment, using square channel geometry. The method was first shown to be suitable to capture the quasisteady lift force that leads to particle cross-streamline migration in channel flow. Then the particle alignment in the flow direction was investigated by calculating the particle relative trajectories as a function of flow inertia and of the ratio between the particle size and channel hydraulic diameter. The flow streamlines were examined around the freely rotating particles at equilibrium, revealing stable small-scale vortices between aligned particles. The streamwise inter-particle spacing between aligned particles at equilibrium was calculated and compared to available experimental data in square channel flow (Gao et al. Microfluidics and Nanofluidics 21, 154 (2017)). The new result highlighted by our numerical simulations is that the inter-particle spacing is unconditionally stable only for a limited number of aligned particles in a single train, the threshold number being dependent on the confinement (particle-to-channel size ratio) and on the Reynolds number. For instance, when the particle Reynolds number is ≈ 1 and the particle-to-channel height size ratio is ≈ 0.1, the maximum number of stable aligned particles per train is equal to 3. This agrees with statistics realized on the experiments of (Gao et al. Microfluidics and Nanofluidics 21, 154 (2017)). It is argued that when several particles are hydrodynamically connected moving as a unique structure (the train) with a steady streamwise velocity, large-scale hydrodynamic perturbations induced at the train scale prohibit small-scale vortex connection between the leading and second particles, forcing the leading particle to leave the train. arXiv:1810.08670v1 [physics.flu-dyn]

show abstract

Pairwise interactions in inertially driven one-dimensional microfluidic crystals

Cited by 22 publications

References 22 publications

A flowing pair of particles in inertial microfluidics

A flowing pair of particles in inertial microfluidics

Particle pairs and trains in inertial microfluidics

Conditional stability of particle alignment in finite-Reynolds-number channel flow

Contact Info

Product

Resources

About