Stochastic Jetting and Dripping in Confined Soft Granular Flows.

  title={Stochastic Jetting and Dripping in Confined Soft Granular Flows.},
  author={Michael Bogdan and Andrea Montessori and Adriano Tiribocchi and Fabio Bonaccorso and Marco Lauricella and Leon Jurkiewicz and Sauro Succi and Jan Guzowski},
  journal={Physical review letters},
  volume={128 12},
We report new dynamical modes in confined soft granular flows, such as stochastic jetting and dripping, with no counterpart in continuum viscous fluids. The new modes emerge as a result of the propagation of the chaotic behavior of individual grains-here, monodisperse emulsion droplets-to the level of the entire system as the emulsion is focused into a narrow orifice by an external viscous flow. We observe avalanching dynamics and the formation of remarkably stable jets-single-file granular… 

Figures from this paper

The crucial role of adhesion in the transmigration of active droplets through interstitial orifices
Active fluid droplets are a class of soft materials exhibiting autonomous motion sustained by an energy supply. Such systems have been shown to capture motility regimes typical of biological cells and
Machine learning assisted droplet trajectories extraction in dense emulsions and their analysis
This work analyzes trajectories obtained by YOLO and DeepSORT algorithms of dense emulsion systems simulated by Lattice Boltzmann methods. The results indicate that the individual droplet’s moving
DropTrack - automatic droplet tracking using deep learning for microfluidic applications
The results highlight the effectiveness of hybrid datasets in training an object detector network and provide a valuable strategy to save significant resources while developing similar applications to analyze challenging bio/micro/microfluidic experimental data.


Capillary threads and viscous droplets in square microchannels
We experimentally study the formation and evolution of threads containing more viscous liquids surrounded by less viscous, immiscible liquids through hydrodynamic focusing in square microchannels.
Mesoscale modelling of droplets' self-assembly in microfluidic channels.
The ability of the mesoscale model to accurately reproduce main mechanisms leading to the formation of two basic droplet patterns, in close agreement with experimental evidence, and the device-scale clustering efficiency of the crystal formation process are demonstrated.
Spatial cooperativity in soft glassy flows
This work uses a microfluidic velocimetry technique to characterize the flow of thin layers of concentrated emulsions, confined in gaps of different thicknesses by surfaces of different roughnesses, and shows that a rather simple non-local flow rule can account for all the velocity profiles.
Drop formation in microfluidic cross-junction: jetting to dripping to jetting transition
The regimes of drop generation were studied in a Dolomite microfluidic device which combined both hydrodynamic and geometrical flow focusing over a broad range of flow rates. A series of aqueous
Microfluidic crystals: dynamic interplay between rearrangement waves and flow.
This work explores the flow of microfluidic crystals, when submitted to a given driving pressure, and finds that the flow velocity is linked to the finite number of elements in the channel width, and presents discontinuities when the crystal structure changes.
Confinement and viscosity ratio effect on droplet break-up in a concentrated emulsion flowing through a narrow constriction.
The results represent a critical step towards the understanding of the physics governing instability in concentrated emulsions and provide a direct guide for the rational design of microchannels and the choice of operation parameters to increase the throughput of the droplet interrogation step while preserving droplet integrity and assay accuracy.
Dripping to jetting transitions in coflowing liquid streams.
It is shown that in a coflowing stream this transition from dripping to jetting is characterized by a state diagram that depends on the capillary number of the outer fluid and the WeberNumber of the inner fluid.
Hysteresis and avalanches in two-dimensional foam rheology simulations.
It is found that the dynamics of topological rearrangements depend sensitively on the structural disorder, and as the shear rate or structural disorder increases, the topological events become more correlated and their power spectra change from that of white noise toward 1/f noise.
Droplet clusters: exploring the phase space of soft mesoscale atoms.
Three-dimensional structures--mesoscale "atoms"--comprising up to N=8 aqueous droplets compressed in a liquid shell are reported, showing highly nonoptimum packing and hence interfacial energy much higher than that of the lowest-energy state-exhibit finite energy barriers that prevent restructuring and relaxation of energy.
Nonlinear dynamics of a flow-focusing bubble generator: an inverted dripping faucet.
Experimental observations support inertia-dominated dynamics of the interface, and suggest the possible similarity to the dynamics of a topologically inverted counterpart of this system, that is, a dripping faucet.