Physical Review Fluids

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Recent articles in Physical Review Fluids
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Electric field induced droplet deformation and breakup in confined shear flows

Wed, 03/06/2019 - 10:00

Author(s): Rattandeep Singh, Supreet Singh Bahga, and Amit Gupta

Deformation or breakup of a droplet suspended in confined shear flows and subjected to an electric field is investigated numerically. A contrasting behavior of the droplet depending upon the electrical properties of the fluids is reported.

[Phys. Rev. Fluids 4, 033701] Published Wed Mar 06, 2019

Instability of precession driven Kelvin modes: Evidence of a detuning effect

Wed, 03/06/2019 - 10:00

Author(s): Johann Herault, André Giesecke, Thomas Gundrum, and Frank Stefani

Experiments in a precessing cylinder filled with water show signatures of azimuthally drifting inertial waves. These modes originate from a triadic resonance and their characteristic frequency dependence is explained by a detuning mechanism due to the slowdown of the background flow.

[Phys. Rev. Fluids 4, 033901] Published Wed Mar 06, 2019

Transport of flexible fibers in confined microchannels

Tue, 03/05/2019 - 10:00

Author(s): Jean Cappello, Mathias Bechert, Camille Duprat, Olivia du Roure, François Gallaire, and Anke Lindner

The deformation of a flexible fiber transported perpendicularly in a plug flow in a confining microchannel is studied using experiments and numerical simulations. The fiber deflection, resulting from an inhomogeneous force distribution, is a function of an elastoviscous number and fiber confinement.

[Phys. Rev. Fluids 4, 034202] Published Tue Mar 05, 2019

Orientation dynamics of nonspherical particles under surface gravity waves

Tue, 03/05/2019 - 10:00

Author(s): Michelle H. DiBenedetto, Jeffrey R. Koseff, and Nicholas T. Ouellette

Nonspherical particles in the ocean are relevant to phenomena such as microplastics, plankton and sediment. Experimental results of the orientation dynamics of nonspherical particles in waves find competition between the waves and the inertial effects on particle orientation.

[Phys. Rev. Fluids 4, 034301] Published Tue Mar 05, 2019

Linear and nonlinear regimes of an inertial wave attractor

Tue, 03/05/2019 - 10:00

Author(s): Maxime Brunet, Thierry Dauxois, and Pierre-Philippe Cortet

We report an experimental study of the nonlinear regime of an inertial wave attractor revealing the emergence of a triadic resonance instability with singular features. The attractor properties are shown to be well described by introducing a turbulent viscosity in the linear attractor model.

[Phys. Rev. Fluids 4, 034801] Published Tue Mar 05, 2019

Excitation and resonant enhancement of axisymmetric internal wave modes

Tue, 03/05/2019 - 10:00

Author(s): S. Boury, T. Peacock, and P. Odier

Inspired by geophysical phenomena, such as storm generated internal waves in the ocean, an experimental study is performed using an axisymmetric internal wave generator. Radial and vertical confinement lead to Bessel-shaped standing waves and resonance effects caused by multiple cavity reflections.

[Phys. Rev. Fluids 4, 034802] Published Tue Mar 05, 2019

Effects of trailing edge shape on vortex formation by pitching panels of small aspect ratio

Mon, 03/04/2019 - 10:00

Author(s): Arman Hemmati, Tyler Van Buren, and Alexander J. Smits

A study examines wake dynamics for oscillating foils with different trailing edges and relates them to unsteady propulsive performance of the foil. It also connects the main wake features to surface pressure fluctuations on both faces of the foil during an oscillatory period.

[Phys. Rev. Fluids 4, 033101] Published Mon Mar 04, 2019

Vibration-induced thermal instabilities in supercritical fluids in the absence of gravity

Mon, 03/04/2019 - 10:00

Author(s): Deewakar Sharma, Arnaud Erriguible, Gurunath Gandikota, Daniel Beysens, and Sakir Amiroudine

Supercritical fluids when subjected to vibrations in the direction parallel and normal to the interface lead to Rayleigh-vibrational and parametric instabilities. These instabilities arise in the thermal boundary layer as a result of strong thermomechanical coupling.

[Phys. Rev. Fluids 4, 033401] Published Mon Mar 04, 2019

Thermocapillary and electrohydrodynamic effects on the stability of dynamic contact lines

Mon, 03/04/2019 - 10:00

Author(s): Devin T. Conroy, Leonardo Espín, Omar K. Matar, and Satish Kumar

Electric fields and temperature fields significantly modify the stability of dynamic contact lines. Electric fields enhance the growth of transverse perturbations, whereas temperature fields can enhance or suppress growth depending on the direction of the temperature gradient.

[Phys. Rev. Fluids 4, 034001] Published Mon Mar 04, 2019

Steady flow regimes and mixing performance in arrow-shaped micro-mixers

Mon, 03/04/2019 - 10:00

Author(s): A. Mariotti, C. Galletti, E. Brunazzi, and M. V. Salvetti

The steady flow regimes and mixing performances of arrow-like micro-mixers are investigated experimentally and by DNS for varying Re and tilting angles. Arrow-mixers trigger mixing at lower Re than for T-mixers, but for large tilting angles mixing does not increase monotonically with Re.

[Phys. Rev. Fluids 4, 034201] Published Mon Mar 04, 2019

Taylor dispersion in the presence of cross flow and interfacial mass transfer

Fri, 03/01/2019 - 10:00

Author(s): Tiras Y. Lin and Eric S. G. Shaqfeh

A solute flowing in a pressure-driven channel flow experiences an enhanced effective axial dispersion coefficient due to the transverse velocity gradients. An investigation shows how this phenomenon, known as Taylor dispersion, is affected by cross flow and mass transfer at the wall.

[Phys. Rev. Fluids 4, 034501] Published Fri Mar 01, 2019

Acoustogravitational balance in climbing films

Thu, 02/28/2019 - 10:00

Author(s): Amihai Horesh, Daniel Khaikin, Mackenzie Karnilaw, Anna Zigelman, and Ofer Manor

In experiments a surface acoustic wave at 20 Mhz propagating down a vertical surface induces a liquid film to climb up the surface against gravity.

[Phys. Rev. Fluids 4, 022001(R)] Published Thu Feb 28, 2019

Numerical investigation of the collapse of a static bubble at the free surface in the presence of neighbors

Thu, 02/28/2019 - 10:00

Author(s): Digvijay Singh and Arup Kumar Das

Formation of a liquid jet and drop as a consequence of the bursting of a bubble in symmetric and asymmetric neighborhoods is modeled numerically. We find that unbalanced interaction of neighbors forces the jet and drop to bend towards the absent bubbles.

[Phys. Rev. Fluids 4, 023602] Published Thu Feb 28, 2019

Breakup of elongated droplets in microfluidic T-junctions

Thu, 02/28/2019 - 10:00

Author(s): Cees Haringa, Conrad de Jong, Duong A. Hoang, Luis M. Portela, Chris R. Kleijn, Michiel T. Kreutzer, and Volkert van Steijn

Long droplets entering a microfluidic T-junction get trapped below, and break beyond, a critical capillary number, which is determined theoretically and experimentally in this work.

[Phys. Rev. Fluids 4, 024203] Published Thu Feb 28, 2019

Self-diffusion in compressible gas flow through a microconduit

Wed, 02/27/2019 - 10:00

Author(s): Di Shen and Kang Ping Chen

The compressible Navier-Stokes equations already include the self-diffusion effect. Comparisons with 35 experiments show that the self-diffusion effect is too small to account for the mass flow rate enhancement in steady compressible gas flow through a microconduit in the slip flow regime.

[Phys. Rev. Fluids 4, 024202] Published Wed Feb 27, 2019

Low-dimensional representations and anisotropy of model rotor versus porous disk wind turbine arrays

Wed, 02/27/2019 - 10:00

Author(s): Elizabeth H. Camp and Raúl Bayoán Cal

We experimentally compare wakes within three-bladed rotor and porous disk wind turbine arrays using PIV measurements and proper orthogonal decomposition. Disparities between rotors and disks with important implications for wind turbine simulations is found.

[Phys. Rev. Fluids 4, 024610] Published Wed Feb 27, 2019

No return to reflection symmetry in freely decaying homogeneous turbulence

Wed, 02/27/2019 - 10:00

Author(s): Katsunori Yoshimatsu and Yukio Kaneda

A certain homogeneous fully developed turbulence, which was initially reflection asymmetric at large scales, is studied theoretically and numerically. It is shown that the turbulence does not relax to any reflection symmetric state, even in the energy containing range.

[Phys. Rev. Fluids 4, 024611] Published Wed Feb 27, 2019

Rayleigh-Taylor convective dissolution in confined porous media

Tue, 02/26/2019 - 10:00

Author(s): Marco De Paoli, Francesco Zonta, and Alfredo Soldati

RT instability and convection in confined porous media is examined via DNS. Interactions between gravity and diffusion produce efficient fluid mixing, and a superlinear asymptotic growth of the mixing rate is observed and modeled for the first time. Potential geophysical applications are envisioned.

[Phys. Rev. Fluids 4, 023502] Published Tue Feb 26, 2019

Exponential scaling in early-stage agglomeration of adhesive particles in turbulence

Tue, 02/26/2019 - 10:00

Author(s): Sheng Chen, Shuiqing Li, and Jeffrey S. Marshall

Agglomeration of adhesive particles in turbulence is investigated. The size distribution of early-stage agglomerates follows a unified exponential scaling. A new agglomeration kernel containing information about the fractal structure of agglomerates and the sticking probability is constructed.

[Phys. Rev. Fluids 4, 024304] Published Tue Feb 26, 2019

Experimental study of soft porous lubrication

Tue, 02/26/2019 - 10:00

Author(s): Zenghao Zhu, Sheldon Weinbaum, and Qianhong Wu

Lessons learned from the motion of red cells in capillaries are applied to a novel experimental study of soft porous lubrication, which conclusively demonstrates a dramatic decrease of friction coefficient with tremendously enhanced pore pressure as a planar board glides over a soft porous layer.

[Phys. Rev. Fluids 4, 024305] Published Tue Feb 26, 2019