Physical Review Fluids

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Recent articles in Physical Review Fluids
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Explosive Leidenfrost droplets

Wed, 01/09/2019 - 10:00

Author(s): Florian Moreau, Pierre Colinet, and Stéphane Dorbolo

Experiments show that Leidenfrost droplets made of water and surfactant undergo a violent explosion. This unexpected behavior is triggered by the formation of a shell during the evaporation. Shortly afterwards, the temperature increases above the boiling point, leading to bubble growth, shell stretching, and explosion.

[Phys. Rev. Fluids 4, 013602] Published Wed Jan 09, 2019

Quantifying hydrodynamic collective states of magnetic colloidal spinners and rollers

Wed, 01/09/2019 - 10:00

Author(s): Y. Wang, S. Canic, G. Kokot, A. Snezhko, and I. S. Aranson

This work expands the scope of modern computational tools for predictive modeling of microscopic active systems, and provides insight into the intricate role of hydrodynamic interaction on the onset of collective behavior of living and synthetic active matter.

[Phys. Rev. Fluids 4, 013701] Published Wed Jan 09, 2019

Frictional force on sliding drops

Wed, 01/09/2019 - 10:00

Author(s): Joel Koplik

A recent claim that a liquid drop sliding on a solid has a transition from static to sliding friction, based on an ingenious but indirect experiment, disagrees with molecular dynamics simulations which directly measure the forces involved.

[Phys. Rev. Fluids 4, 014001] Published Wed Jan 09, 2019

Numerical investigation of the coupling of vibrational nonequilibrium and turbulent mixing using state-specific description

Tue, 01/08/2019 - 10:00

Author(s): Romain Fiévet, Venkat Raman, Stephen Voelkel, and Philip L. Varghese

To understand the coupling between mixing and vibrational relaxation, a novel state-specific model is solved inside a direct numerical simulation of a compressible jet. It is found that gas compressibility effects trigger vibrational nonequilibrium, while turbulence affects the states’ population.

[Phys. Rev. Fluids 4, 013401] Published Tue Jan 08, 2019

Timescale and spatial distribution of local plastic events in a two-dimensional microfluidic crystal

Tue, 01/08/2019 - 10:00

Author(s): Ya Gai, Alison Bick, and Sindy K. Y. Tang

The timescale of droplet rearrangement in a 2D concentrated emulsion—a microfluidic crystal—displays 3 regimes with 2 transitions with increasing capillary number. The loss of order in the crystal flow corresponds to the second transition involving a solid to liquid-like transition of the emulsion.

[Phys. Rev. Fluids 4, 014201] Published Tue Jan 08, 2019

Simulations of clean drops rising into a layer of dissolved surfactant

Tue, 01/08/2019 - 10:00

Author(s): David W. Martin, Tamunotubo George, and François Blanchette

A computational study of clean drops rising into a layer of dissolved surfactant, modeling oil drops rising in the ocean, is presented. Drops are first accelerated by surface tension gradients before being slowed by accumulated surfactants on their surface.

[Phys. Rev. Fluids 4, 014302] Published Tue Jan 08, 2019

Announcement: PRFluids Publishes Invited Perspective on Modeling Imbalances in the Atmosphere and Ocean

Mon, 01/07/2019 - 10:00

[Phys. Rev. Fluids 4, 010001] Published Mon Jan 07, 2019

Recent progress in modeling imbalance in the atmosphere and ocean

Mon, 01/07/2019 - 10:00

Author(s): Bruce R. Sutherland, Ulrich Achatz, Colm-cille P. Caulfield, and Jody M. Klymak

How does energy input at planetary scales in the atmosphere and ocean ultimately reach scales small enough to be dissipated efficiently through turbulence? Here we describe advances in understanding the underlying instability and transport processes achieved through observations, theory, and numerical simulations, with a focus inspired in part by a February 2018 interdisciplinary workshop on the subject held at the Banff International Research Station.

[Phys. Rev. Fluids 4, 010501] Published Mon Jan 07, 2019

Ballistics of self-jumping microdroplets

Mon, 01/07/2019 - 10:00

Author(s): Pierre Lecointre, Timothée Mouterde, Antonio Checco, Charles T. Black, Atikur Rahman, Christophe Clanet, and David Quéré

Droplets merging on hydrophobic nanocones jump off, and the takeoff speed is found to be maximum at microscale, below and above which viscosity and inertia, respectively, cap this speed. Microdroplets successively experience strong lift off, slow flight, and smooth landing, which impedes bouncing.

[Phys. Rev. Fluids 4, 013601] Published Mon Jan 07, 2019

Hydrodynamics of bacteriophage migration along bacterial flagella

Fri, 01/04/2019 - 10:00

Author(s): Panayiota Katsamba and Eric Lauga

Bacteriophage viruses infect and replicate within bacteria. Some phages ride along the flagellar filaments used by bacteria for propulsion. Here we confirm a 40-year old hypothesis and show that infection can be induced by hydrodynamic forces due to rotation of flagellar filaments.

[Phys. Rev. Fluids 4, 013101] Published Fri Jan 04, 2019

Local linearity, coherent structures, and scale-to-scale coupling in turbulent flow

Fri, 01/04/2019 - 10:00

Author(s): Lei Fang, Sanjeeva Balasuriya, and Nicholas T. Ouellette

Starting from the notion that a coherent structure is a set of fluid elements with very similar behavior, the idea of linear neighborhoods is introduced. These kinematic structures also play a role in the flow dynamics, in that the spectral energy transfer inside them is higher than it is outside.

[Phys. Rev. Fluids 4, 014501] Published Fri Jan 04, 2019

Miscible density-driven flows in heterogeneous porous media: Influences of correlation length and distribution of permeability

Fri, 01/04/2019 - 10:00

Author(s): Qian Li, Weihua Cai, Feng-Chen Li, Bingxi Li, and Ching-Yao Chen

We numerically evaluate permeable heterogeneity effects on gravity-driven miscible porous media flows relevant to underground CO2 storage. For typical finger widths below correlation length we find largest variation measures among random realizations, and lowest mean due to the resonant effect.

[Phys. Rev. Fluids 4, 014502] Published Fri Jan 04, 2019

Three-wave interactions among surface gravity waves in a cylindrical container

Wed, 01/02/2019 - 10:00

Author(s): Guillaume Michel

While at least four plane surface gravity waves are required to make a resonant interaction, only three modes are required in a cylindrical container. An experiment is carried out to isolate and characterize such a triad interaction.

[Phys. Rev. Fluids 4, 012801(R)] Published Wed Jan 02, 2019

Effect of normal contact forces on the stress in shear rate invariant particle suspensions

Wed, 01/02/2019 - 10:00

Author(s): J. J. J. Gillissen and H. J. Wilson

We theoretically predict, that, in sphere suspensions, hydrodynamic interaction forces produce a negligible first normal stress difference, while contact forces produce a positive first normal stress difference.

[Phys. Rev. Fluids 4, 013301] Published Wed Jan 02, 2019

Sticking collision between a sphere and a textured wall in a viscous fluid

Wed, 01/02/2019 - 10:00

Author(s): Thibault Chastel and Anne Mongruel

High-frequency laser interferometry is used to resolve the motion of an immersed sphere prior to its collision with a wetted textured wall below the bouncing transition. The measurements reveal different sphere dynamics resulting from the texture-induced modification of the lubrication drag force.

[Phys. Rev. Fluids 4, 014301] Published Wed Jan 02, 2019

Classification of internal solitary wave breaking over a slope

Wed, 01/02/2019 - 10:00

Author(s): Keisuke Nakayama, Takahiro Sato, Kenji Shimizu, and Leon Boegman

This study proposes a classification for breaker types when internal solitary waves shoal over a uniform slope. We use an extended data set of extant published experimental data and our own numerical experiments. We find that a single index delineates collapsing and plunging breakers.

[Phys. Rev. Fluids 4, 014801] Published Wed Jan 02, 2019

Evaporation-driven convective flows in suspensions of nonmotile bacteria

Fri, 12/28/2018 - 10:00

Author(s): Jocelyn Dunstan, Kyoung J. Lee, Yongyun Hwang, Simon F. Park, and Raymond E. Goldstein

Suspensions of bioluminiscent bacteria display convective motions reminiscent of classical bioconvection, but this poses a conundrum, as these organisms lack flagella-driven motility under the conditions studied. Instead, evaporation of the salty growth medium is found to drive the convection.

[Phys. Rev. Fluids 3, 123102] Published Fri Dec 28, 2018

Fingering instability transition in radially tapered Hele-Shaw cells: Insights at the onset of nonlinear effects

Fri, 12/28/2018 - 10:00

Author(s): Pedro H. A. Anjos, Eduardo O. Dias, and José A. Miranda

Weakly nonlinear analysis is used to study fingering instabilities in radially tapered (converging and diverging) Hele-Shaw cells. It is found that changes in the capillary number modify the interface instability behavior and the finger shapes relative to what usually occurs in parallel-plate cells.

[Phys. Rev. Fluids 3, 124004] Published Fri Dec 28, 2018

Modification of turbulence and stratification of stably stratified turbulent channel flows by finite-size particles

Fri, 12/28/2018 - 10:00

Author(s): Juwon Jang and Changhoon Lee

Neutrally buoyant finite-size particles laden in stratified turbulent channel flows are found to enhance internal gravity waves, thus blocking heat transfer. In the near-wall region, these particles are preferentially located in the high-speed streaks.

[Phys. Rev. Fluids 3, 124309] Published Fri Dec 28, 2018

Extracting the spectrum of a flow by spatial filtering

Fri, 12/28/2018 - 10:00

Author(s): Mahmoud Sadek and Hussein Aluie

Can you gain “insight” by relinquishing some of your sight? Indeed, we show how to quantify the energy content of various structures in a flow by observing it through “eyeglasses” of varying strength. We also introduce a new class of “lenses” with a simple design which yield more accurate results.

[Phys. Rev. Fluids 3, 124610] Published Fri Dec 28, 2018