Mesoscale modelling of near-contact interactions for complex flowing interfaces

Montessori, Andrea; Lauricella, Marco; Tirelli, Nicola; Succi, Sauro

doi:10.1017/jfm.2019.372

Cited by 64 publications

(62 citation statements)

References 66 publications

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“…Continuum theories, combined with suitable numerical approaches (such as lattice Boltzmann methods 39 – 41 and boundary integral method 38 ) have proven capable to capture characteristic features observed in double emulsion experiments, such as their production within microchannels 40 , the typical shape deformations of the capsule (elliptical and bullet-like) under moderate shear flows 42 – 44 , as well as more complex dynamic behaviors, such as the breakup of the enveloping shell occurring under intense fluid flows 45 . However, much less is known about the dynamics of more sophisticated systems, such as multiple emulsions with distinct inner cores, theoretically investigated only by a few authors to date 38 , 39 .…”

Section: Introductionmentioning

confidence: 99%

The vortex-driven dynamics of droplets within droplets

et al. 2021

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Understanding the fluid-structure interaction is crucial for an optimal design and manufacturing of soft mesoscale materials. Multi-core emulsions are a class of soft fluids assembled from cluster configurations of deformable oil-water double droplets (cores), often employed as building-blocks for the realisation of devices of interest in bio-technology, such as drug-delivery, tissue engineering and regenerative medicine. Here, we study the physics of multi-core emulsions flowing in microfluidic channels and report numerical evidence of a surprisingly rich variety of driven non-equilibrium states (NES), whose formation is caused by a dipolar fluid vortex triggered by the sheared structure of the flow carrier within the microchannel. The observed dynamic regimes range from long-lived NES at low core-area fraction, characterised by a planetary-like motion of the internal drops, to short-lived ones at high core-area fraction, in which a pre-chaotic motion results from multi-body collisions of inner drops, as combined with self-consistent hydrodynamic interactions. The onset of pre-chaotic behavior is marked by transitions of the cores from one vortex to another, a process that we interpret as manifestations of the system to maximize its entropy by filling voids, as they arise dynamically within the capsule.

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Section: Introductionmentioning

confidence: 99%

The vortex-driven dynamics of droplets within droplets

et al. 2021

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“…The computational model used in this work is based on a recent development of a Lattice Boltzmann (LB) approach for multicomponent flows [33,35,29], aimed at capturing the effects of near-contact interactions operating at the fluid interface level. Such method has been found to correctly reproduce the collision between bouncing droplets [33] and to simulate the dynamics of soft flowing crystals in a flow focuser [8].…”

Section: Methodsmentioning

confidence: 99%

“…The effects of near-contact forces are modelled via a mesoscopic repulsive force, which competes with capillary forces (surface tension) to prevent droplet coalescence and ensuing coarsening of the material [33].…”

Section: Introductionmentioning

confidence: 99%

Microvorticity fluctuations affect the structure of thin fluid films

et al. 2019

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The dynamic interaction of complex fluid interfaces is highly sensitive to near-contact interactions occurring at the scale of ten of nanometers. Such interactions are difficult to analyse because they couple selfconsistently to the dynamic morphology of the evolving interface, as well as to the hydrodynamics of the interstitial fluid film. In this work, we show that, above a given magnitude threshold, near-contact interactions trigger non-trivial micro-vorticity patterns, which in turn affect the effective near-contact interactions, giving rise to persistent fluctuating ripples arXiv:2005.06214v1 [cond-mat.soft] 13 May 2020 at the fluid interface. In such regime, near-contact interactions may significantly affect the macroscopic arrangement of emulsion configurations, such as those arising in soft-flowing microfluidic crystals.

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“…The coupling and communication across the different regions take place within a handshaking region where the hydrodynamic information is exchanged between the two representations. In this work, we propose a hybrid numerical scheme based on the lattice Boltzmann method (LB) [7][8][9][10] and the multiparticle collision dynamics (MPCD), [11,12] capable of predicting the correct macroscopic hydrodynamics also in the presence of multilevel grids (one and two levels), while retaining the correct thermal fluctuations, embedded by default in the multiparticle collision method.…”

Section: Doi: 101002/adts201900250mentioning

confidence: 99%

“…This implies smaller number of time steps required for transport coefficients to reach their asymptotic values. [12] As a consequence, the restriction on maximum number of particles per cell (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), which commonly applies for the SRD, does not apply to the MPCD-AT, where the relaxation times scale as (ln N) −1 . [11] It was pointed out that the hydrodynamic limit of the multiparticle collision dynamics approach corresponds to the fluctuating Navier-Stokes equation for athermal and weakly compressible fluids.…”

Section: Multiparticle Collision Dynamics With Andersen Thermostatmentioning

confidence: 99%

A Multiresolution Mesoscale Approach for Microscale Hydrodynamics

Montessori

Tiribocchi

Lauricella

et al. 2020

Advcd Theory and Sims

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A new class of multiscale scheme is presented for micro‐hydrodynamic problems based on a dual representation of the fluid observables. The hybrid model is first tested against the classical flow between two parallel plates and then applied to a plug flow within a micrometer‐sized striction and a shear flow within a microcavity. Both cases demonstrate the capability of the multiscale approach to reproduce the correct macroscopic hydrodynamics also in the presence of refined grids (one and two levels), while retaining the correct thermal fluctuations, embedded in the multiparticle collision method. This provides the first step toward a novel class of fully mesoscale hybrid approaches able to capture the physics of fluids at the micro‐ and nanoscales whenever a continuum representation of the fluid falls short of providing the complete physical information, due to a lack of resolution and thermal fluctuations.

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Mesoscale modelling of near-contact interactions for complex flowing interfaces

Cited by 64 publications

References 66 publications

The vortex-driven dynamics of droplets within droplets

The vortex-driven dynamics of droplets within droplets

Microvorticity fluctuations affect the structure of thin fluid films

A Multiresolution Mesoscale Approach for Microscale Hydrodynamics

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