Physical Review Fluids

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Recent articles in Physical Review Fluids
Updated: 21 hours 43 min ago

Apparent slip mechanism between two spheres based on solvent rheology: Theory and implication for the shear thinning of non-Brownian suspensions

Mon, 12/10/2018 - 10:00

Author(s): A. Vázquez-Quesada, Pep Español, and M. Ellero

The slip behavior observed experimentally between close spheres is described by an analytical model in terms of the apparent shear-thinning rheology of the solvent. The results compare well with experiments and bridge the hidden solvent shear-thinning theory for suspensions with slip-based models.

[Phys. Rev. Fluids 3, 123302] Published Mon Dec 10, 2018

Assessment of continuum breakdown for chemically reacting wake flows

Mon, 12/10/2018 - 10:00

Author(s): Sharanya Subramaniam and Kelly A. Stephani

Enabled by a newly developed species perturbation parameter, an analysis identifies forebody surface chemistry, among all other competing thermophysical processes, as the key contributor to continuum breakdown in hypersonic reacting wake flows.

[Phys. Rev. Fluids 3, 123401] Published Mon Dec 10, 2018

Thermal convection in rotating spherical shells: Temperature-dependent internal heat generation using the example of triple-$α$ burning in neutron stars

Mon, 12/10/2018 - 10:00

Author(s): F. Garcia, F. R. N. Chambers, and A. L. Watts

A new convective model in rotating spherical shells, with a temperature-dependent internal heat source, is studied by means of three-dimensional simulations. The potential applicability of the results to the evolution of thermonuclear bursts in accreting neutron star oceans is explored.

[Phys. Rev. Fluids 3, 123501] Published Mon Dec 10, 2018

Observation of two branches in the hindered settling function at low Reynolds number

Mon, 12/10/2018 - 10:00

Author(s): T. A. Brzinski, III and D. J. Durian

Combining new and old data, we find that particle settling speeds are well-described by the empirical Richardson-Zaki function up to jamming, but surprisingly, there are separate branches for Brownian and non-Brownian particles with a crossover at an extraordinarily large Peclet number of 108.

[Phys. Rev. Fluids 3, 124303] Published Mon Dec 10, 2018

Dual-plane turbulent jets and their non-Gaussian velocity fluctuations

Mon, 12/10/2018 - 10:00

Author(s): Yi Zhou, Koji Nagata, Yasuhiko Sakai, and Tomoaki Watanabe

Direct numerical simulations show that for dual-plane jet flows with different separation lengths, the streamwise evolutions of various statistics along the centerline all scale with the proposed jet-interaction length scale. The spatial evolution of the −5/3 scaling law is closely related to the non-Gaussian velocity fluctuations.

[Phys. Rev. Fluids 3, 124604] Published Mon Dec 10, 2018

Non-Kolmogorov dissipation in a turbulent planar jet

Mon, 12/10/2018 - 10:00

Author(s): G. C. Layek and Sunita

Adopting Lie symmetry group theory both Kolmogorov and non-Kolmogorov scaling and dissipation laws are explored theoretically for a turbulent planar jet. We find that the jet entrainment coefficient varies with streamwise distance when non-Kolmogorov scaling laws hold.

[Phys. Rev. Fluids 3, 124605] Published Mon Dec 10, 2018

Rayleigh-Darcy convection with hydrodynamic dispersion

Fri, 12/07/2018 - 10:00

Author(s): Baole Wen, Kyung Won Chang, and Marc A. Hesse

Two-dimensional numerical simulations of high Rayleigh number convection in a porous medium explore the effect of increasing anisotropy of mechanical dispersion on the convective pattern and flux.

[Phys. Rev. Fluids 3, 123801] Published Fri Dec 07, 2018

Bubble stabilization by the star-nosed mole

Thu, 12/06/2018 - 10:00

Author(s): Alexander B. Lee and David L. Hu

The star-nosed mole sniffs for prey underwater by rapidly blowing a bubble, then sucking it back in before the bubble detaches from the nose. Experiments show how the bizarre shape of the mole’s nose might contribute to stabilizing bubbles during the sniff, enabling this behavior.

[Phys. Rev. Fluids 3, 123101] Published Thu Dec 06, 2018

Local velocity variations for a drop moving through an orifice: Effects of edge geometry and surface wettability

Thu, 12/06/2018 - 10:00

Author(s): Ankur D. Bordoloi and Ellen K. Longmire

Velocity fields determined within and surrounding a drop moving through an orifice reveal the relative importance of local deformation, fluid rotation, and dissipation in the surrounding fluid as well as the coupling between fluid inertia and contact-line motion.

[Phys. Rev. Fluids 3, 123602] Published Thu Dec 06, 2018

Particle entrainment in unsteady-uniform granular avalanches

Thu, 12/06/2018 - 10:00

Author(s): Michele Larcher, Anna Prati, and Luigi Fraccarollo

Experiments on unsteady granular avalanches, which are uniform in the flow direction, allow for observations of the evolution of the flow depth, the velocity profile, and the concentration distribution. A simple, physically-based, analytic model is proposed to fit the observations.

[Phys. Rev. Fluids 3, 124302] Published Thu Dec 06, 2018

Two-sphere swimmers in viscoelastic fluids

Wed, 12/05/2018 - 10:00

Author(s): Charu Datt, Babak Nasouri, and Gwynn J. Elfring

Swimmers comprised of two rigid spheres that oscillate periodically along their axis of symmetry are examined. In viscoelastic fluids, the swimmers propel in the direction of the smaller sphere when the two spheres are of different sizes.

[Phys. Rev. Fluids 3, 123301] Published Wed Dec 05, 2018

Lateral vesicle migration in a bounded shear flow: Viscosity contrast leads to off-centered solutions

Wed, 12/05/2018 - 10:00

Author(s): Abdessamad Nait-Ouhra, Achim Guckenberger, Alexander Farutin, Hamid Ez-Zahraouy, Abdelilah Benyoussef, Stephan Gekle, and Chaouqi Misbah

The lateral migration of a vesicle (a model of red blood cells) in a bounded shear flow is investigated numerically. It is found that there exists an off-center stable steady state of the vesicle in addition to the usual centerline, depending on the initial position and viscosity contrast.

[Phys. Rev. Fluids 3, 123601] Published Wed Dec 05, 2018

Drag upon a sphere suspended in a low magnetic-Reynolds number MHD channel flow

Wed, 12/05/2018 - 10:00

Author(s): Jules Delacroix and Laurent Davoust

As a first step towards the description of magnetohydrodynamic (MHD) dispersed two-phase flows, a permanent MHD channel flow past a stationary sphere is numerically investigated, highlighting the gradual emergence of atypical MHD flow patterns, among them a genuine “ghost column.”

[Phys. Rev. Fluids 3, 123701] Published Wed Dec 05, 2018

Effect of layout on asymptotic boundary layer regime in deep wind farms

Wed, 12/05/2018 - 10:00

Author(s): Juliaan Bossuyt, Charles Meneveau, and Johan Meyers

This paper presents wind tunnel data for 56 different layouts of a scaled wind farm with 100 porous disk models. The data indicates that a nonuniform streamwise spacing between turbine rows can increase power output in the fully developed and entrance regions of large wind farms.

[Phys. Rev. Fluids 3, 124603] Published Wed Dec 05, 2018

Rectification of chaotic fluid motion in two-dimensional turbulence

Tue, 12/04/2018 - 10:00

Author(s): N. Francois, H. Xia, H. Punzmann, and M. Shats

In two-dimensional turbulence, we show how to create devices able to feed on the turbulent fluid motion by coupling with underlying features of the energy cascade. By changing the shape of the device, we can turn it into a self-propelled vehicle or a rotor powered by turbulence.

[Phys. Rev. Fluids 3, 124602] Published Tue Dec 04, 2018

Modeling internal rogue waves in a long wave-short wave resonance framework

Tue, 12/04/2018 - 10:00

Author(s): H. N. Chan, R. H. J. Grimshaw, and K. W. Chow

Rogue waves in the interior of a stratified fluid are modeled as special breathers (pulsating modes) arising from long-wave–short-wave resonance. Features like the existence condition and waveforms contrast sharply with those of free surface waves governed by the nonlinear Schrödinger equation.

[Phys. Rev. Fluids 3, 124801] Published Tue Dec 04, 2018

Sedimentation of a rigid helix in viscous media

Mon, 12/03/2018 - 10:00

Author(s): Martina Palusa, Joost de Graaf, Aidan Brown, and Alexander Morozov

A theoretical study of rigid helices sedimenting under gravity finds they either follow a helical path downwards, or exhibit complicated oscillations close to the horizontal orientation.

[Phys. Rev. Fluids 3, 124301] Published Mon Dec 03, 2018

Energy transport due to pressure diffusion enhanced by helicity and system rotation in inhomogeneous turbulence

Mon, 12/03/2018 - 10:00

Author(s): Kazuhiro Inagaki and Fujihiro Hamba

It is known that turbulent energy is rapidly transferred in the direction of the rotation axis in a rotating system, in comparison with the nonrotating case. A new turbulence model of the energy flux predicting this phenomenon is proposed and discussed in terms of turbulent helicity.

[Phys. Rev. Fluids 3, 124601] Published Mon Dec 03, 2018

Universal scaling law in frictional non-Brownian suspensions

Fri, 11/30/2018 - 10:00

Author(s): Frédéric Blanc, Enzo D'Ambrosio, Laurent Lobry, François Peters, and Elisabeth Lemaire

Suspensions made of either faceted or spherical particles behave in quite different ways. However, experiments show that it is possible to unify their behavior by considering the contact contribution to the viscosity that is evaluated through shear reversal experiments.

[Phys. Rev. Fluids 3, 114303] Published Fri Nov 30, 2018

Mass entrainment-based model for separating flows

Fri, 11/30/2018 - 10:00

Author(s): F. Stella, N. Mazellier, P. Joseph, and A. Kourta

The recirculation flow bounding a forced separating and reattaching shear layer is modeled. Experimental results emphasize that mass entrainment is a key parameter on which the parameters of the model scale. It is shown that an inexpensive and easily deployable sensor can be used to estimate the backflow.

[Phys. Rev. Fluids 3, 114702] Published Fri Nov 30, 2018