Physical Review Fluids

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Recent articles in Physical Review Fluids
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Total mechanical energy transport lines and attractors in separating turbulent boundary layers

Thu, 01/23/2020 - 10:00

Author(s): Wen Wu, Rajat Mittal, and Charles Meneveau

The fate of total mechanical energy during flow separation is visualized through energy transport lines. A spiral node attractor inside the separation bubble and three segments of the wall are identified as attracting sets.

[Phys. Rev. Fluids 5, 012601(R)] Published Thu Jan 23, 2020

Direct numerical simulation of the sedimentation of a particle pair in a shear-thinning fluid

Thu, 01/23/2020 - 10:00

Author(s): Xitong Zhang, Haihu Liu, Ya Zhang, and Liang Wang

Sedimentation of a particle pair in a shear-thinning fluid is studied for varying generalized Archimedes number. Unlike in the Newtonian fluid, one more group of multiple stable states is identified, and the drafting-kissing-tumbling state disappears when the shear-thinning effect is strong enough.

[Phys. Rev. Fluids 5, 014304] Published Thu Jan 23, 2020

Laboratory experiments modeling the transport and deposition of sediments by glacial plumes rising under an ice shelf

Tue, 01/21/2020 - 10:00

Author(s): Bruce R. Sutherland, Madelaine G. Rosevear, and Claudia Cenedese

Particles that descend from a buoyant current are carried back toward the source resulting in a sediment deposit whose depth decreases linearly with distance from the source beyond a recirculation zone. The experimental results are used to predict the deposit of sediments from glacial plumes occurring around Antarctica.

[Phys. Rev. Fluids 5, 013802] Published Tue Jan 21, 2020

Effects of a nonadiabatic wall on hypersonic shock/boundary-layer interactions

Tue, 01/21/2020 - 10:00

Author(s): Pedro S. Volpiani, Matteo Bernardini, and Johan Larsson

The effects of wall thermal conditions on the canonical case of an impinging shock wave interacting with a turbulent boundary layer is a topic that remains under explored. Direct numerical simulations are used to study the flow properties of hypersonic-shock–boundary-layer interactions with distinct wall thermal conditions and shock angles.

[Phys. Rev. Fluids 5, 014602] Published Tue Jan 21, 2020

Multiscale control of active emulsion dynamics

Thu, 01/16/2020 - 10:00

Author(s): Livio Nicola Carenza, Luca Biferale, and Giuseppe Gonnella

The strength of the activity of polar particles is varied in two-dimensional Lattice Boltzmann simulations of a liquid crystal model of active material. The simulations find phase separation and then mixing in the chaotic flow.

[Phys. Rev. Fluids 5, 011302(R)] Published Thu Jan 16, 2020

Pore-scale dynamics and the multiphase Darcy law

Thu, 01/16/2020 - 10:00

Author(s): Ying Gao, Qingyang Lin, Branko Bijeljic, and Martin J. Blunt

Time-resolved synchrotron x-ray microtomography combined with pressure measurements during two-phase displacement in porous media identifies three flow regimes. Intermittent occupancy creates temporary high-conductivity connections, leading to a power-law trend of pressure gradient with flow rate.

[Phys. Rev. Fluids 5, 013801] Published Thu Jan 16, 2020

Hidden prompt splashing by corona splashing at drop impact on a smooth dry surface

Wed, 01/15/2020 - 10:00

Author(s): Taku Ashida, Masao Watanabe, Kazumichi Kobayashi, Hiroyuki Fujii, and Toshiyuki Sanada

Using a high-speed camera, three types of splashing are identified as drops impact on a surface; the types of splashing depend on the surface roughness and on the ambient gas pressure.

[Phys. Rev. Fluids 5, 011601(R)] Published Wed Jan 15, 2020

Thixotropic pumping in a cylindrical pipe

Wed, 01/15/2020 - 10:00

Author(s): David Pritchard, Andrew I. Croudace, and Stephen K. Wilson

The response of thixotropic fluids to applied forces depends not just on the instantaneous forces but on how they change over time. A model of thixotropic flow in a pipe illustrates how this can lead to the net transport of fluid under oscillatory forcing at intermediate Deborah numbers and that the effect vanishes in the limit of either a small or a large Deborah number (i.e., very slow or very fast forcing).

[Phys. Rev. Fluids 5, 013303] Published Wed Jan 15, 2020

Inertial migration of neutrally buoyant particles in superhydrophobic channels

Wed, 01/15/2020 - 10:00

Author(s): Tatiana V. Nizkaya, Evgeny S. Asmolov, Jens Harting, and Olga I. Vinogradova

The effective anisotropic hydrodynamic slip of a channel wall decorated by superhydrophobic grooves is shown to alter the equilibrium positions of neutrally buoyant particles and to generate their motion transverse to the pressure gradient.

[Phys. Rev. Fluids 5, 014201] Published Wed Jan 15, 2020

Two regime cooling in flow induced by a spark discharge

Tue, 01/14/2020 - 10:00

Author(s): Bhavini Singh, Lalit K. Rajendran, Pavlos P. Vlachos, and Sally P. M. Bane

Cooling of the flow induced by a spark plasma discharge is found to occur at two different rates: an initially fast cooling regime followed by a slow cooling regime. Convective cooling in the fast regime contributes to 30–50% of the total cooling and occurs within the first millisecond of the induced flow.

[Phys. Rev. Fluids 5, 014501] Published Tue Jan 14, 2020

Drop dynamics of viscoelastic filaments

Mon, 01/13/2020 - 10:00

Author(s): Hrishikesh Pingulkar, Jorge Peixinho, and Olivier Crumeyrolle

As a capillary bridge of a viscoelastic fluid breaks to form beads-on-a-string, diameter-space-time diagrams are used to reproduce the position of the minimum diameter on the filament, the asymmetric satellite drop distribution and the movement of the filament in the direction of drop coalescence. Further, the size of the largest drop and the number of drops formed are quantified as a function of polymer concentration.

[Phys. Rev. Fluids 5, 011301(R)] Published Mon Jan 13, 2020

Experimental evidence of settling retardation in a turbulence column

Mon, 01/13/2020 - 10:00

Author(s): Y. Akutina, T. Revil-Baudard, J. Chauchat, and O. Eiff

An experimental investigation of the settling velocity of solid particles in homogeneous isotropic turbulence finds that for different shapes of particles, the settling is slowed down by the turbulence. A relationship between modified settling velocity and turbulence intensity is obtained.

[Phys. Rev. Fluids 5, 014303] Published Mon Jan 13, 2020

Formation of power-law scalings of spectra and multiscale coherent structures in the near-field of grid-generated turbulence

Mon, 01/13/2020 - 10:00

Author(s): Tatsuya Yasuda, Susumu Goto, and John Christos Vassilicos

An investigation shows that 5/3 and -7/3 frequency spectra of turbulent energy and pressure, respectively, appear along shear layers in the very near-field of grid turbulence via interactions between vortices due to shedding and shear-layer instability.

[Phys. Rev. Fluids 5, 014601] Published Mon Jan 13, 2020

Viscous reflection of internal waves from a slope

Mon, 01/13/2020 - 10:00

Author(s): T. Kataoka and T. R. Akylas

A weakly nonlinear model is developed that accounts for viscous dissipation in the reflection of an internal wave beam from a uniform slope. The theoretical predictions compare favorably with Navier-Stokes simulations and also explain the poor quantitative agreement of earlier inviscid models with laboratory experiments.

[Phys. Rev. Fluids 5, 014803] Published Mon Jan 13, 2020

Flow structures and kinetic-potential exchange in forced rotating stratified turbulence

Thu, 01/09/2020 - 10:00

Author(s): Tianyi Li, Minping Wan, Jianchun Wang, and Shiyi Chen

Flow structures and the kinetic-potential energy exchange in rotating stratified turbulence are studied by simulations. Differences of cyclonic and anticyclonic vortices are shown. The intense kinetic-potential energy exchange is found to be associated with the cyclonic structures.

[Phys. Rev. Fluids 5, 014802] Published Thu Jan 09, 2020

Asymmetric rectified electric fields generate flows that can dominate induced-charge electrokinetics

Wed, 01/08/2020 - 10:00

Author(s): S. M. H. Hashemi Amrei, Gregory H. Miller, and William D. Ristenpart

Extant theories for induced-charge electrokinetics (ICEK) sometimes fail to predict even the correct direction of flow. By combining the recently discovered phenomenon of asymmetric rectified electric fields with a generalized form of ICEK, this long-standing dilemma is explained.

[Phys. Rev. Fluids 5, 013702] Published Wed Jan 08, 2020

Flow induced by an oscillating sphere in probing complex viscosity of polymer solutions

Tue, 01/07/2020 - 10:00

Author(s): Yanzhen He, Lu Li, Takashi Taniguchi, Remco Tuinier, and Tai-Hsi Fan

Flow pattern and apparent complex viscosity are derived explicitly for viscoelastic flow induced by an oscillatory colloid in polymer solutions, with depletion effect taken into account. Within the linear regime, the model can be used to interpret active and passive microrheological measurements.

[Phys. Rev. Fluids 5, 013302] Published Tue Jan 07, 2020

Transverse jet lock-in and quasiperiodicity

Tue, 01/07/2020 - 10:00

Author(s): Takeshi Shoji, Elijah W. Harris, Andrea Besnard, Stephen G. Schein, and Ann R. Karagozian

An experimental study explores the dynamics of lock-in and quasiperiodicity phenomena associated with upstream shear layer instabilities for a gaseous transverse jet exposed to axisymmetric excitation. Various dynamical responses are dependent on the jet-to-crossflow momentum flux ratio.

[Phys. Rev. Fluids 5, 013901] Published Tue Jan 07, 2020

Experimental investigation of three-dimensional flow around particles in a turbulent channel flow

Tue, 01/07/2020 - 10:00

Author(s): Farzad Ahmadi, Sean Sanders, and Sina Ghaemi

Simultaneous three-dimensional measurement of the velocity of beads and the surrounding flow is carried out in a turbulent channel flow. The results show that the quasi-steady drag is not sufficient to model the dynamics of the beads in the near-wall region.

[Phys. Rev. Fluids 5, 014302] Published Tue Jan 07, 2020

Fine vortex structure and flow transition to the geostrophic regime in rotating Rayleigh-Bénard convection

Mon, 01/06/2020 - 10:00

Author(s): Jun-Qiang Shi, Hao-Yuan Lu, Shan-Shan Ding, and Jin-Qiang Zhong

High-resolution measurements of velocity fields reveal the fine structure of vortices and indicate flow-regime transition in rapidly rotating Rayleigh-Bénard convection.

[Phys. Rev. Fluids 5, 011501(R)] Published Mon Jan 06, 2020