Physical Review Fluids
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
[Phys. Rev. Fluids 4, 010001] Published Mon Jan 07, 2019
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
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
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
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
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
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
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
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
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
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
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
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
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
Author(s): Xi Zhao, Jianbo Tang, and Jing Liu
We conduct experiments on Faraday wave patterns and bouncing droplets with a high-density/surface tension liquid metal fluid. Bouncing liquid metal droplets can be sustained on the wavy surface, self-assembling into various lattice structures which can be switched with an electric field.
[Phys. Rev. Fluids 3, 124804] Published Thu Dec 27, 2018
Author(s): Chenliang Li, Shi-Ping Wang, A-Man Zhang, and Yunlong Liu
The dynamic behavior of two neighboring nanobubbles is investigated for various gas-liquid-solid interactions. Two neighboring unsaturated surface nanobubbles can form a gas-rich layer on a solid surface, as long as the interaction between the solid and the gas is sufficiently strong.
[Phys. Rev. Fluids 3, 123604] Published Wed Dec 26, 2018
Author(s): Simon Tusch, Etienne Loiseau, Al-Hair Al-Halifa, Kamel Khelloufi, Emmanuèle Helfer, and Annie Viallat
Side view of the full rotation of a two-phase giant vesicle doing a tanktreading motion under a shear rate of 5 s−1. The major axis of the vesicle oscillates showing the vesicle swings similarly to a red blood cell.
[Phys. Rev. Fluids 3, 123605] Published Wed Dec 26, 2018
Author(s): Sang-Hyeon Lee, Sang Jun Lee, Ji San Lee, Kamel Fezzaa, and Jung Ho Je
Transient dynamics of a Leidenfrost vapor layer in drop impact is studied using x-ray imaging. It is shown that a vapor disk first forms, growing in thickness, following Fourier’s law. At a certain thickness, ripples generate near the edge and propagate to the center by capillary waves, improving evaporation.
[Phys. Rev. Fluids 3, 124308] Published Wed Dec 26, 2018
Author(s): Nairita Pal, Susan Kurien, Timothy Clark, Denis Aslangil, and Daniel Livescu
We study buoyancy-driven variable-density homogeneous turbulence with a two-point spectral closure model and assess model accuracy relative to direct numerical simulations using standard metrics. The model captures statistics of spectral distributions and global means at low and high Atwood numbers.
[Phys. Rev. Fluids 3, 124608] Published Wed Dec 26, 2018