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