Physical Review Fluids
Author(s): Andrea Armaroli, Debbie Eeltink, Maura Brunetti, and Jérôme Kasparian
An envelope equation to model the propagation of surface waves in deep viscous fluids is proposed. The dispersion relation comprising viscosity and surface tension is expressed as an operator and used to generalize the universal nonlinear Schrödinger equation and quantify nonlinear damping.
[Phys. Rev. Fluids 3, 124803] Published Mon Dec 17, 2018
Apparent slip and drag reduction for the flow over superhydrophobic and lubricant-impregnated surfaces
Author(s): Edoardo Alinovi and Alessandro Bottaro
The flow within microscopic indentations filled with a lubricant fluid is studied by varying viscosity ratio, surface tension, and lubricant-to-working-fluid volume fraction. This yields protrusion heights that readily quantify the drag reduction of a lubricant-impregnated microstructured surface.
[Phys. Rev. Fluids 3, 124002] Published Thu Dec 13, 2018
Author(s): Darwin Darakananda, André Fernando de Castro da Silva, Tim Colonius, and Jeff D. Eldredge
This works shows for the first time that an inexpensive ensemble of low-order vortex models can accurately capture the aerodynamics of a low Reynolds number separated flow, even when disturbed by gusts, when it assimilates measured surface pressures.
[Phys. Rev. Fluids 3, 124701] Published Thu Dec 13, 2018
Author(s): Jim Thomas and Ray Yamada
A new amplitude equation that captures the effect of arbitrary topography on surface waves is presented. It can be integrated more quickly than the fully nonlinear equations, while accurately capturing the wave dynamics.
[Phys. Rev. Fluids 3, 124802] Published Thu Dec 13, 2018
Author(s): M. Couliou and R. Monchaux
We numerically investigate temporal aspects of turbulent spot spreading in plane Couette flow for transitional Reynolds numbers, focusing on streamwise spreading. From the topology of turbulent spots and associated large-scale flows, we propose a decomposition of the streamwise growth rate.
[Phys. Rev. Fluids 3, 123901] Published Wed Dec 12, 2018
Investigation of the phenomena occurring near the liquid–vapor interface during evaporation of water at low pressures
Author(s): Mohammad Amin Kazemi, David S. Nobes, and Janet A. W. Elliott
The three-dimensional flow generated below a liquid-vapor meniscus during low-pressure water evaporation is quantified with experiments using scanning particle image velocimetry and compared with an extensive numerical model. Results show how buoyancy effects in the liquid may suppress thermocapillary flows at the interface.
[Phys. Rev. Fluids 3, 124001] Published Wed Dec 12, 2018
Erratum: Scaling laws of top jet drop size and speed from bubble bursting including gravity and inviscid limit [Phys. Rev. Fluids <b>3</b>, 091601(R) (2018)]
Author(s): Alfonso M. Gañán-Calvo
[Phys. Rev. Fluids 3, 129901] Published Wed Dec 12, 2018
Optimal design of deterministic lateral displacement device for viscosity-contrast-based cell sorting
Author(s): Gökberk Kabacaoğlu and George Biros
Deterministic lateral displacement (DLD) is used to sort red blood cells (RBCs) by their mechanical properties. This enables rapid medical diagnosis of diseases such as malaria. A systematic way of discovering new DLD designs for efficient sorting of RBCs with similar mechanical properties is proposed.
[Phys. Rev. Fluids 3, 124201] Published Tue Dec 11, 2018
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