Article
|
Open Access
Featured
-
-
Article
| Open AccessMediation of lubricated air films using spatially periodic dielectrophoretic effect
The violent splash of a droplet caused by residual air pockets trapped during impact on a solid surface appears inevitable. Vo and Tran show how to vent the drop on short notice for a smooth touchdown, harnessing dielectrophoretic forces to create dynamic drainage channels.
- Quoc Vo
- & Tuan Tran
-
Article
| Open AccessVelocity bias in intrusive gas-liquid flow measurements
Estimating velocities in gas liquid flows is of importance in many engineering applications. Hohermuth et al. show that previous bubble velocities obtained from intrusive probes have been underestimated and provide a correction scheme for more accurate velocity measurements.
- B. Hohermuth
- , M. Kramer
- & D. Valero
-
Article
| Open AccessLiquid flow reversibly creates a macroscopic surface charge gradient
Reactions at the interface between mineral surfaces and flowing liquids are ubiquitous in nature. Here the authors explore, using surface-specific sum frequency generation spectroscopy and numeric calculations, how the liquid flow affects the charging and dissolution rates leading to flow-dependent charge gradients along the surface.
- Patrick Ober
- , Willem Q. Boon
- & Mischa Bonn
-
Article
| Open AccessPump-probe X-ray holographic imaging of laser-induced cavitation bubbles with femtosecond FEL pulses
Cavitation bubbles show many nonlinear characteristics of liquid and gas phase. Here the authors demonstrate coherent diffractive imaging of cavitation bubble using infrared pump and XFEL probe and discuss the formation and evolution of the bubbles.
- M. Vassholz
- , H. P. Hoeppe
- & T. Salditt
-
Article
| Open AccessRobust learning from noisy, incomplete, high-dimensional experimental data via physically constrained symbolic regression
Reinbold et al. propose a physics-informed data-driven approach that successfully discovers a dynamical model using high-dimensional, noisy and incomplete experimental data describing a weakly turbulent fluid flow. This approach is relevant to other non-equilibrium spatially-extended systems.
- Patrick A. K. Reinbold
- , Logan M. Kageorge
- & Roman O. Grigoriev
-
Article
| Open AccessNon-associative phase separation in an evaporating droplet as a model for prebiotic compartmentalization
Prebiotic compartmentalization could prove essential for the evolution of life. Guo et al. show that liquid-liquid separation in an aqueous two-phase system driven by evaporation may already suffice to facilitate chemical processes required for the RNA world hypothesis.
- Wei Guo
- , Andrew B. Kinghorn
- & Ho Cheung Shum
-
Article
| Open AccessSlippery damper of an overlay for arresting and manipulating droplets on nonwetting surfaces
Controlled deposition of droplets on super-repellent surfaces is a challenging task in many practical applications. Han et al. show that already a rather thin encapsulating film of a highly viscous liquid can fine tune droplet impact as to suppress both rebound and splash.
- Xing Han
- , Wei Li
- & Liqiu Wang
-
Article
| Open AccessThe role of drop shape in impact and splash
The dynamics of droplet impact and splash is important in many applications, yet its analysis involves difficult intertwined aspects. Here Liu et al. make shape parametrically accessible to experiment, with ferrofluidic drops passing a magnetic field in a defined way.
- Qingzhe Liu
- , Jack Hau Yung Lo
- & Lei Xu
-
Article
| Open AccessEarly turbulence and pulsatile flows enhance diodicity of Tesla’s macrofluidic valve
Nguyen et al. take a fresh look at Tesla’s concept of an asymmetric fluidic conduit. They show that for alternating flow at high frequencies the device can almost be operated as a diode, enabled by a transition to turbulent-like flow at rather low Reynolds numbers.
- Quynh M. Nguyen
- , Joanna Abouezzi
- & Leif Ristroph
-
Article
| Open AccessMicron-scale phenomena observed in a turbulent laser-produced plasma
Turbulence effects explored use macroscale systems in general. Here the authors generate a turbulent plasma using laser irradiation of a solid target and study the dynamics of the plasma flow at the micron-scale by using scattering of an XFEL beam.
- G. Rigon
- , B. Albertazzi
- & M. Koenig
-
Article
| Open AccessRapid heat discharge during deep-sea eruptions generates megaplumes and disperses tephra
A novel model for submarine tephra dispersal by hydrothermal megaplumes is proposed. The energy flux inferred from our model aligns with megaplume observations, and suggests that the catastrophic release of hot crustal fluids, as opposed to lava heating, is responsible for megaplume generation.
- Samuel S. Pegler
- & David J. Ferguson
-
Article
| Open AccessHydrodynamic instability at impact interfaces and planetary implications
The authors describe a dynamic surface instability between impacting materials, showing that a region of mixing grows between two media. The study implies that this can explain mixed compositions and textures in certain meteorites.
- Avi Ravid
- , Robert I. Citron
- & Raymond Jeanloz
-
Article
| Open AccessDiffusion in dense supercritical methane from quasi-elastic neutron scattering measurements
Methane is abundant in the Universe, is an important energy carrier and a model system for fundamental studies. Here, the authors measure the self-diffusion coefficient of supercritical methane at ambient temperature up to the freezing pressure, and find a different behavior than expected based on previous models.
- Umbertoluca Ranieri
- , Stefan Klotz
- & Livia E. Bove
-
Article
| Open AccessActive carpets drive non-equilibrium diffusion and enhanced molecular fluxes
Fick’s laws describe the essential physics of diffusion, but it is challenging to extend them to systems out of equilibrium. The authors derive the diffusivity of particles near active carpets - a surface covered with hydrodynamic actuators, which provides a framework for transport in living matter.
- Francisca Guzmán-Lastra
- , Hartmut Löwen
- & Arnold J. T. M. Mathijssen
-
Article
| Open AccessEngineering and characterization of gymnosperm sapwood toward enabling the design of water filtration devices
Gymnosperm sapwood is an abundantly available material to construct water filters but the material’s behaviour as a filter is poorly understood and challenges such as short shelf live have not been addressed. Here, the authors develop guidelines for the design and fabrication of xylem filters and demonstrate gravity-operated filters with a shelf life of more than two years for the removal of contaminants from spring, tap and ground water.
- Krithika Ramchander
- , Megha Hegde
- & Rohit Karnik
-
Article
| Open AccessLeidenfrost droplet trampolining
The classic Leidenfrost phenomenon is familiar, yet its physics is rather complex. Graeber et al. observe the unexpected development of repeated hopping of a droplet trampolining on its own vapor cushion on a hot plate and show under which conditions this self-initiated motion occurs.
- Gustav Graeber
- , Kartik Regulagadda
- & Dimos Poulikakos
-
Article
| Open AccessAnatomy of subcritical submarine flows with a lutocline and an intermediate destruction layer
This study investigates the underlying physical mechanisms of turbidity currents travelling thousands of miles in confined submarine settings, rather than diffusing after short distance. Using high resolution simulations with up to a billion grid points helps to understand the evolving layered structure of a current.
- Jorge S. Salinas
- , S. Balachandar
- & M. I. Cantero
-
Article
| Open AccessEvaporation-driven transport-control of small molecules along nanoslits
Nanofluidic channels offer the possibility to process small molecules or colloids, but transport control meets serious challenges. Seo et al. use evaporation-driven advective flow to establish a versatile manipulation scheme of the fluid carrier, disposing of external connectors.
- Sangjin Seo
- , Dogyeong Ha
- & Taesung Kim
-
Article
| Open AccessSniffing speeds up chemical detection by controlling air-flows near sensors
Sniff frequency naturally varies with animal type due to allometric scaling. Using data from live animals and a machine olfactory system, Spencer et al. reveal a deeper reason for sniffing with implications for designing gas detectors: the sniff is adapted to efficient odor detection.
- Thomas L. Spencer
- , Adams Clark
- & David L. Hu
-
Article
| Open AccessMoulding hydrodynamic 2D-crystals upon parametric Faraday waves in shear-functionalized water surfaces
There is a renewed interest in Faraday waves patterns in the field of nonlinear metamaterials due to their tunable templating capacity. Kharbedia et al. show that free-standing water surfaces with ordered patterns can be generated and controlled by the Faraday waves with help of stiffening surfactants.
- Mikheil Kharbedia
- , Niccolò Caselli
- & Francisco Monroy
-
Article
| Open AccessSymmetry breaking propulsion of magnetic microspheres in nonlinearly viscoelastic fluids
A self-propelling agent at small Reynolds numbers usually requires a fore-aft asymmetry in order to circumvent the scallop theorem. Here Rogowski et al. show that this need not be true for motion in non-linear viscoelastic fluids, where an initial symmetry may be broken spontaneously.
- Louis William Rogowski
- , Jamel Ali
- & Min Jun Kim
-
Article
| Open AccessHow ice grows from premelting films and water droplets
Melting and crystallization of ice close to the triple point is mediated by a thin liquid layer of water. Within an extended theoretical-numerical model, Sibley et al. capture both equilibrium properties and kinetic aspects of the film evolution to arrive at a broader perspective of how ice grows.
- David N. Sibley
- , Pablo Llombart
- & Luis G. MacDowell
-
Article
| Open AccessSlowing down DNA translocation through solid-state nanopores by edge-field leakage
Solid-state nanopores can serve as single molecule sensors for DNA sequencing, but the current designs suffer from fast DNA translocation so low detectivity. Wang et al. slow down and control the translocation speed by 5 orders of magnitude using a leakage field generated at the nanopore tip.
- Ceming Wang
- , Sebastian Sensale
- & Hsueh-Chia Chang
-
Article
| Open AccessThe vortex-driven dynamics of droplets within droplets
Multi-emulsion droplets may lead to improved designs of soft materials or drug formulations. Tiribocchi et al. show that in typical situations expected during microfluidic post-processing, the dynamical distribution of emulsified droplets is dictated by the internal vortices of the host droplet.
- A. Tiribocchi
- , A. Montessori
- & D. A. Weitz
-
Article
| Open AccessSelf-attenuation of extreme events in Navier–Stokes turbulence
Whether a turbulent flow would inevitably develop singular behavior at the smallest length scales is an ongoing intriguing debate. Using large-scale numerical simulations, Buaria et al. find an unexpected non-linear mechanism which counteracts local vorticity growth instead of enabling it.
- Dhawal Buaria
- , Alain Pumir
- & Eberhard Bodenschatz
-
Article
| Open AccessPhase synchronization of fluid-fluid interfaces as hydrodynamically coupled oscillators
The robust production of droplets by microfluidic T-junctions is a well-established technique. Um et al. demonstrate how the mutual interaction between droplets can be used to achieve additional control including the simultaneous release of droplets caused by synchronization phenomena.
- Eujin Um
- , Minjun Kim
- & Joonwoo Jeong
-
Article
| Open AccessReconstructing the electrical structure of dust storms from locally observed electric field data
Electrification is naturally generated in dust storms but its structures remain largely unknown. Here, the authors present an inversion model to reconstruct such structures based on the locally observed electric field data, showing that dust storms exhibit a three-dimensional mosaic charge pattern.
- Huan Zhang
- & You-He Zhou
-
Article
| Open AccessElectron hydrodynamics in anisotropic materials
In some materials electrons can behave hydrodynamically, exhibiting phenomena associated with classical viscous fluids. In this theory work, the authors show that the symmetries of the crystal lattices in which the electrons reside can lead to additional unique hydrodynamic effects.
- Georgios Varnavides
- , Adam S. Jermyn
- & Prineha Narang
-
Article
| Open AccessForecasting extreme stratospheric polar vortex events
Extreme events high up in the winter stratosphere are known to influence our weather and their predictability has potential to improve seasonal weather forecasts. Here, the authors examine factors that influence their generation and highlight a previously unrecognised sensitivity to the upper equatorial stratosphere.
- L. J. Gray
- , M. J. Brown
- & J. Anstey
-
Article
| Open AccessSpatial ultrasound modulation by digitally controlling microbubble arrays
The authors introduce a dynamic spatial ultrasound modulator, based on digitally generated patterns of microbubbles controlled by a complementary metal–oxide–semiconductor (CMOS) chip. They achieve reshaping of incident plane waves into complex acoustic images and demonstrate dynamic parallel assembly of microparticles.
- Zhichao Ma
- , Kai Melde
- & Peer Fischer
-
Article
| Open AccessKinetics of motile solitons in nematic liquid crystals
Electric field induced convective instabilities in liquid crystal slabs can assume a localized shape. The authors show how to generate, manipulate and shepard these dissipative solitary excitations that do not require topological constraints for stabilization.
- Satoshi Aya
- & Fumito Araoka
-
Article
| Open AccessGiant spin hydrodynamic generation in laminar flow
In spin hydrodynamic generation originating from the coupling of mechanical rotation in a fluid and electron spin, fluid vorticity can be converted into an electric voltage via a spin current. Here, the authors demonstrate experimentally that the energy conversion in a laminar flow regime is strongly enhanced over the turbulent regime.
- R. Takahashi
- , H. Chudo
- & E. Saitoh
-
Article
| Open AccessThe effect of flow on swimming bacteria controls the initial colonization of curved surfaces
Bacterial colonization of surfaces has a profound environmental, technological and medical impact. Here, Secchi et al. show how fluid flow affects the magnitude and location of bacterial colonization on curved surfaces through its coupling with cell morphology and motility.
- Eleonora Secchi
- , Alessandra Vitale
- & Roman Stocker
-
Article
| Open AccessMagnetic cilia carpets with programmable metachronal waves
Synthetic hair-like structures (cilia) controlled by an external field have been developed, especially for microfluidic applications. Here, Gu et al. make soft artificial cilia carpets with programmable magnetization patterns and utilize them to achieve pumping and locomotion in a soft robotic model.
- Hongri Gu
- , Quentin Boehler
- & Bradley J. Nelson
-
Article
| Open AccessSearch and rescue at sea aided by hidden flow structures
Every year, hundreds of people die at sea because of vessel accidents, and a key challenge in reducing these fatalities is to make Search and Rescue (SAR) planning more efficient. Here, the authors uncover hidden flow features that attract floating objects, providing specific information for optimal SAR planning.
- Mattia Serra
- , Pratik Sathe
- & George Haller
-
Article
| Open AccessHydrodynamic slip can align thin nanoplatelets in shear flow
Current theories predict that a plate-like particle rotates continuously in a shear flow. Kamal et al. instead show that even nanometric hydrodynamic slip may induce a thin plate-like particle to adopt a stable orientation, and discuss implications of this effect for flow processing of 2D nanomaterials.
- Catherine Kamal
- , Simon Gravelle
- & Lorenzo Botto
-
Article
| Open AccessA transition to stable one-dimensional swimming enhances E. coli motility through narrow channels
Most biological and artificial self-propelled particles tend to be attracted by solid walls on their swimming pathways. Vizsnyiczai et al. show that, unexpectedly, confining E. coli cells inside a channel triggers stable locomotion along the channel axis once the channel is narrower than a critical value.
- Gaszton Vizsnyiczai
- , Giacomo Frangipane
- & Roberto Di Leonardo
-
Article
| Open AccessHigh-throughput cell and spheroid mechanics in virtual fluidic channels
High-throughput rheological measurements of cells and cell clusters by microfluidics is limited by fixed channel dimensions. Here the authors create virtual fluidic channels inside the cuvette of commercial flow cytometers to dynamically tune channel cross section to enable rheological measurements from cells and cell clusters.
- Muzaffar H. Panhwar
- , Fabian Czerwinski
- & Oliver Otto
-
Article
| Open AccessDimension-reconfigurable bubble film nanochannel for wetting based sensing
Dimensions and the surface properties of the nanochannels are vital to the functions and applications of nano-fluidic devices. Here Ma et al. studied the film thickness of a Bretherton bubble in a microcapillary and demonstrate the liquid film can be used for label-free biosensing.
- Yu Ma
- , Miao Sun
- & Yanbo Xie
-
Article
| Open AccessUltrafast photomechanical transduction through thermophoretic implosion
Here, the authors observe that laser illumination allows to displace a vial of nanoparticle solution over centimetre-scale distances. In order to explain this, they describe a novel mechanism for laser propulsion of a macroscopic object, based on light-induced thermophoresis.
- Nikita Kavokine
- , Shuangyang Zou
- & Lydéric Bocquet
-
Article
| Open AccessMicrofluidic control over topological states in channel-confined nematic flows
It is interesting phenomenon that chiral order can emerge in intrinsically achiral liquid crystals. Here Čopar et al. demonstrate achiral-to-chiral transition of the nematic liquid crystals flow in microfluidic channels and their behaviour, stability, and dependence on geometric and material parameters.
- Simon Čopar
- , Žiga Kos
- & Uroš Tkalec
-
Article
| Open AccessA first-principle mechanism for particulate aggregation and self-assembly in stratified fluids
Aggregation of matter, common in stratified fluid systems, is essential to the carbon cycle and ocean ecology. Although the current understanding of aggregation involves only collision and adhesion, here Camassa et al. reveal a self-assembly phenomenon arising solely from diffusion-induced flows.
- Roberto Camassa
- , Daniel M. Harris
- & Richard M. McLaughlin
-
Article
| Open AccessMagnetotactic bacteria in a droplet self-assemble into a rotary motor
It remains peculiar how to generate macroscopic work by harnessing the microscopic activity of living or synthetic agents like bacteria or micro-robots. Vincenti et al. show a biological rotary motor by self-assembling magnetotactic bacteria inside a droplet, producing a net torque on the droplet surface.
- Benoit Vincenti
- , Gabriel Ramos
- & Eric Clement
-
Article
| Open AccessWetting transitions in droplet drying on soft materials
It has been shown previously that substrate viscoelasticity affects surface wettability. Here the authors observe a wetting transition during drying of droplets on such substrates and elucidate it with high resolution force field measurements thereby determining its dependence on substrate properties.
- Julia Gerber
- , Tobias Lendenmann
- & Dimos Poulikakos
-
Article
| Open AccessControlling collective rotational patterns of magnetic rotors
A challenge of magnetically-actuated devices is to obtain different behaviours from each component under the same driving field. Here the authors tune the dipolar interactions between rotors to obtain different rotational behaviours when actuated by a magnetic field leading to complex collective dynamics.
- Daiki Matsunaga
- , Joshua K. Hamilton
- & Ramin Golestanian
-
Article
| Open AccessActive control of viscous fingering using electric fields
When a viscous fluid is displaced by a less viscous phase between two plates, a finger-like instability occurs. Here the authors demonstrate how applying an external electric field can suppress the fingering instability without the need to alter the fluid flow rate or the gap geometry.
- Tao Gao
- , Mohammad Mirzadeh
- & Martin Z. Bazant
-
Article
| Open AccessCapillary orbits
It is known that liquid drops can be levitated by continuous vapour flow above a liquid surface. Here the authors combine the ultra-low friction provided by the bath with the interaction force between two drops due to interface deformations to study the dynamics of interactions between multiple objects.
- Anaïs Gauthier
- , Devaraj van der Meer
- & Guillaume Lajoinie
-
Article
| Open AccessExperimental observation of flow fields around active Janus spheres
In order to predict the behaviours of self-propelled particles it is important to understand the fluid disturbances they generate. Here the authors measure the flow-fields around active particles and show that they are in agreement with theoretical predictions which take into account electrokinetic effects.
- Andrew I. Campbell
- , Stephen J. Ebbens
- & Ramin Golestanian
-
Article
| Open AccessEnhanced ion tolerance of electrokinetic locomotion in polyelectrolyte-coated microswimmer
Electrophoretic microswimmers aren’t well suited to function in vivo because electric-field screening reduces their speed in higher ionic-strength solutions. Here the authors propose a microswimmer that exploits high surface conductance to improve this ion tolerance to enable operation in a high salt environment.
- Xiaojun Zhan
- , Jizhuang Wang
- & Jinyao Tang