Physical Review Fluids

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Recent articles in Physical Review Fluids
Updated: 10 hours 27 min ago

Direct numerical simulation of particle sedimentation in a Bingham fluid

Mon, 09/24/2018 - 11:00

Author(s): A. R. Koblitz, S. Lovett, and N. Nikiforakis

Two-dimensional numerical simulations of a suspension of sedimenting particles in a Bingham fluid find three possible regimes: all, a fraction, and none of the particles sedimenting.

[Phys. Rev. Fluids 3, 093302] Published Mon Sep 24, 2018

Viscous fingering of a draining suspension

Mon, 09/24/2018 - 11:00

Author(s): Yun Chen, Frank Malambri, and Sungyon Lee

Viscous fingering arises as air invades a draining viscous suspension. Experiments show that suspended particles delay the onset of fingering but also accelerate its growth rate. In addition, particles of select sizes are observed to coat the channel surfaces and not drain.

[Phys. Rev. Fluids 3, 094001] Published Mon Sep 24, 2018

Confinement effects on gravity-capillary wave turbulence

Mon, 09/24/2018 - 11:00

Author(s): Roumaissa Hassaini and Nicolas Mordant

The effect of confinement in a high-aspect-ratio channel on the statistical properties of weak turbulence of gravity-capillary waves at the surface of water is investigated. Discreteness due to confinement coexists with an almost one-dimensional kinetic sort of wave turbulence.

[Phys. Rev. Fluids 3, 094805] Published Mon Sep 24, 2018

Membrane filtration with complex branching pore morphology

Fri, 09/21/2018 - 11:00

Author(s): Pejman Sanaei and Linda J. Cummings

An idealized first-principles model describing filtration of a feed solution containing small particles in a microstructured porous membrane is presented. Optimal configurations for the pore microstructure are identified in terms of maximizing throughput of filtered fluid and filter lifetime.

[Phys. Rev. Fluids 3, 094305] Published Fri Sep 21, 2018

Inertioelastic Poiseuille flow over a wavy surface

Fri, 09/21/2018 - 11:00

Author(s): Simon J. Haward, Jacob Page, Tamer A. Zaki, and Amy Q. Shen

Experimental evidence is presented for the existence of critical layers in inertioelastic shear flows over wavy surfaces, where theory predicts amplification of the spanwise vorticity.

[Phys. Rev. Fluids 3, 091302(R)] Published Fri Sep 21, 2018

Scaling laws of top jet drop size and speed from bubble bursting including gravity and inviscid limit

Thu, 09/20/2018 - 11:00

Author(s): Alfonso M. Gañán-Calvo

Scaling laws are proposed for the size and the velocity of the droplet which is ejected when a bubble rises to a free surface and bursts. These new scalings consistently incorporate the effect of gravity and the limit of negligible viscosity of the liquid.

[Phys. Rev. Fluids 3, 091601(R)] Published Thu Sep 20, 2018

Onset of three-dimensionality in supersonic flow over a slender double wedge

Wed, 09/19/2018 - 11:00

Author(s): Sidharth GS, Anubhav Dwivedi, Graham V. Candler, and Joseph W. Nichols

An investigation shows that laminar supersonic flow on a 2D compression corner can destabilize to become 3D beyond a critical turn angle. This compressible instability resides in the recirculating flow, producing spiral wall flow patterns postseparation and wall temperature streaks downstream.

[Phys. Rev. Fluids 3, 093901] Published Wed Sep 19, 2018

Turbulent/nonturbulent interfaces in high-resolution direct numerical simulation of temporally evolving compressible turbulent boundary layers

Tue, 09/18/2018 - 11:00

Author(s): Xinxian Zhang, Tomoaki Watanabe, and Koji Nagata

Turbulent-nonturbulent interfaces are studied in temporally evolving subsonic and supersonic turbulent boundary layers by comparing the results of direct numerical simulations with the entrainment model based on a single vortex and the theory for spatially evolving boundary layers.

[Phys. Rev. Fluids 3, 094605] Published Tue Sep 18, 2018

Wake behind a concave curved cylinder

Tue, 09/18/2018 - 11:00

Author(s): Fengjian Jiang, Bjørnar Pettersen, Helge I. Andersson, Jongmin Kim, and Sungtae Kim

The wake behind a concave, curved cylinder configuration is investigated at different Reynolds numbers. Distinctly different wake flow regimes were observed in the computed flow field, including oblique vortex shedding and dislocations. The crucial influence of a straight vertical extension is explored.

[Phys. Rev. Fluids 3, 094804] Published Tue Sep 18, 2018

Inertia-driven jetting regimes in microfluidic coflows

Mon, 09/17/2018 - 11:00

Author(s): Fan Zhang, Arnaud Erriguible, Théo Gavoille, Michaël T. Timko, and Samuel Marre

Inertial breakup modes are identified at microscale for co-flowing jets using a high-pressure mixer.

[Phys. Rev. Fluids 3, 092201(R)] Published Mon Sep 17, 2018

Normal shocks with high upstream pressure

Mon, 09/17/2018 - 11:00

Author(s): William A. Sirignano

A normal compressive shock with upstream pressure from 10 to 500 bar is analyzed for density, enthalpy, entropy, and velocity with nitrogen, oxygen, argon, and carbon dioxide. New descriptions for sound speed, Prandtl’s relation, the Rankine-Hugoniot relation, and Riemann invariants are presented.

[Phys. Rev. Fluids 3, 093401] Published Mon Sep 17, 2018

Rayleigh-Taylor turbulence with singular nonuniform initial conditions

Wed, 09/12/2018 - 11:00

Author(s): L. Biferale, G. Boffetta, A. A. Mailybaev, and A. Scagliarini

Three-dimensional direct numerical simulations of Rayleigh-Taylor turbulence with various initial unstable temperature distributions finds a modified self-similar mixing in the long term.

[Phys. Rev. Fluids 3, 092601(R)] Published Wed Sep 12, 2018

Collisions of drops with an immiscible liquid jet

Wed, 09/12/2018 - 11:00

Author(s): Carole Planchette, Sylvain Petit, Hannes Hinterbichler, and Günter Brenn

The collisions of a drop stream with an immiscible jet are experimentally studied revealing the formation of several complex structures classified in four main regimes. When neither the drops nor the jet fragment,“drops in jet” are observed that could be hardened to produce advanced fibers.

[Phys. Rev. Fluids 3, 093603] Published Wed Sep 12, 2018

Thermophoresis of Janus particles at large Knudsen numbers

Wed, 09/12/2018 - 11:00

Author(s): Tobias Baier, Sudarshan Tiwari, Samir Shrestha, Axel Klar, and Steffen Hardt

At large Knudsen numbers a Janus particle in a thermal gradient shows a preferred orientation. The interplay between rotational diffusion and thermophoretic motion is investigated.

[Phys. Rev. Fluids 3, 094202] Published Wed Sep 12, 2018

Shear-induced migration and orientation of rigid fibers in an oscillatory pipe flow

Mon, 09/10/2018 - 11:00

Author(s): Scott Strednak, Saif Shaikh, Jason E. Butler, and Élisabeth Guazzelli

Fibers in suspension migrate towards the center of the pipe where they are more aligned with the flow. The migration depends on the fraction of the volume of the suspension swept out by the rotating fibers.

[Phys. Rev. Fluids 3, 091301(R)] Published Mon Sep 10, 2018

Forced wakes far from threshold: Stuart-Landau equation applied to experimental data

Mon, 09/10/2018 - 11:00

Author(s): S. Boury, B. Thiria, R. Godoy-Diana, G. Artana, J. E. Wesfreid, and J. D'Adamo

The Stuart-Landau reduced order model is tested with experimental data from the wake of a cylinder wake forced by plasma actuators, finding an important role played by the changing mean flow.

[Phys. Rev. Fluids 3, 091901(R)] Published Mon Sep 10, 2018

Entrainment model for fully-developed wind farms: Effects of atmospheric stability and an ideal limit for wind farm performance

Mon, 09/10/2018 - 11:00

Author(s): Paolo Luzzatto-Fegiz and Colm-cille P. Caulfield

A new model of wind farm aerodynamics establishes an upper bound for power density, which is an order of magnitude larger than achieved by contemporary turbine arrays. The model also provides a one-equation prediction for the output of existing wind farms, and can include atmospheric stability.

[Phys. Rev. Fluids 3, 093802] Published Mon Sep 10, 2018

Asymmetric concentration dependence of segregation fluxes in granular flows

Mon, 09/10/2018 - 11:00

Author(s): Ryan P. Jones, Austin B. Isner, Hongyi Xiao, Julio M. Ottino, Paul B. Umbanhowar, and Richard M. Lueptow

Particles differing in size or density segregate in dense granular flows. In bidisperse mixtures, the sinking (small or heavy) species concentration that maximizes the segregation flux is <50% and decreases with increasing size or density ratio, matching a classic kinetic-sieving model.

[Phys. Rev. Fluids 3, 094304] Published Mon Sep 10, 2018

Extremes, intermittency, and time directionality of atmospheric turbulence at the crossover from production to inertial scales

Mon, 09/10/2018 - 11:00

Author(s): E. Zorzetto, A. D. Bragg, and G. Katul

A study of how the interplay between mechanical and buoyant production of turbulent kinetic energy affects fully developed atmospheric turbulent flows finds impacts both on the frequency of extreme scalar fluctuations and on the time-directional properties of scalar Eulerian measurements.

[Phys. Rev. Fluids 3, 094604] Published Mon Sep 10, 2018

Fluidity, anisotropy, and velocity correlations in frictionless, collisional grain flows

Fri, 09/07/2018 - 11:00

Author(s): Diego Berzi and James T. Jenkins

We propose corrections to the kinetic theory for fluidity in granular flows near random close packing, in order to take account of anisotropy and increases in granular temperature.

[Phys. Rev. Fluids 3, 094303] Published Fri Sep 07, 2018