Latest papers in fluid mechanics
Author(s): D. Lunz and P. D. Howell
Motivated by plasma particles impacting a liquid-metal divertor, an analysis is performed to investigate how a liquid’s free surface is deflected by a moving applied pressure. It is found that the plasma can be swept up and down the liquid in order to spread the heat load, however, this may induce dangerously large deflections.
[Phys. Rev. Fluids 3, 114801] Published Tue Nov 06, 2018
Author(s): Mpumelelo Matse, Peter Berg, and Michael Eikerling
A theoretical model is developed that describes nonlinear coupling between wall deformation and water and ion flows in a charged, deformable nanochannel whose viscoelasticity is governed by the Kelvin-Voigt model. Using continuum mean-field theories for mass and momentum conservation of the solid-li...
[Phys. Rev. E 98, 053101] Published Thu Nov 01, 2018
Author(s): Robert H. Davis and Alexander Z. Zinchenko
Hydrophobic particles are selectively separated from aqueous suspension by a novel oil-in-water binder. The collection efficiency is predicted in this work by a hydrodynamic trajectory analysis, and shown to be greatly enhanced by water permeation through the oil layer.
[Phys. Rev. Fluids 3, 113601] Published Thu Nov 01, 2018
Author(s): Alexandros Alexakis
An investigation of how large-scale flow is affected by changes in the properties of small-scale flows, the layer thickness, and viscosity is presented.
[Phys. Rev. Fluids 3, 114601] Published Thu Nov 01, 2018
Author(s): Yogesh Jethani, Kamal Kumar, A. Sameen, and Manikandan Mathur
Local stability equations are solved along closed fluid particle trajectories in the cylinder wake for Reynolds numbers in the range of 50 to 300. A bifurcation is shown to occur at Re≈250 and is argued to be related to the emergence of the well-known mode-B secondary instability.
[Phys. Rev. Fluids 3, 103902] Published Wed Oct 31, 2018
Author(s): Linlin Fei, Andrea Scagliarini, Andrea Montessori, Marco Lauricella, Sauro Succi, and Kai H. Luo
We further develop a two-range pseudopotential Lattice Boltzmann method for soft flowing systems using tunable surface tension and viscosity ratio. It is applicable to multicomponent fluids with a viscosity-independent disjoining pressure, a key to the microfluidic design of new porous materials.
[Phys. Rev. Fluids 3, 104304] Published Wed Oct 31, 2018
Law of the wall for small-scale streamwise turbulence intensity in high-Reynolds-number turbulent boundary layers
Author(s): B. Ganapathisubramani
Following the dimensional analysis approach of previous works, a law-of-the-wall is proposed for small-scale fluctuations in turbulent wall-flow. Experimental data shows that this universal scaling law extends across almost the entire wall-layer and exhibits a logarithmic trend in the outer region.
[Phys. Rev. Fluids 3, 104607] Published Wed Oct 31, 2018
Author(s): Benjamin Marchetti, Veronica Raspa, Anke Lindner, Olivia du Roure, Laurence Bergougnoux, Élisabeth Guazzelli, and Camille Duprat
A flexible fiber settling in a viscous fluid deforms and reorients to adopt eventually a more or less pronounced “U” shape, regardless of its initial configuration. Three different regimes depending on the relative magnitude of gravitational and elastic forces are identified.
[Phys. Rev. Fluids 3, 104102] Published Tue Oct 30, 2018
Slip-flow lattice-Boltzmann simulations in ducts and porous media: A full rehabilitation of spurious velocities
Author(s): M. Aminpour, S. A. Galindo-Torres, A. Scheuermann, and L. Li
Slip flow in ducts and porous media is simulated using lattice-Boltzmann method incorporated with interfacial force models. The dependence of the results on the viscosity, LBM scheme (D3Q15 and D3Q19) and the relaxation time model (single- or multirelaxation time) is investigated. The severity of sp...
[Phys. Rev. E 98, 043110] Published Mon Oct 29, 2018
Author(s): Zakaria Boujja, Chaouqi Misbah, Hamid Ez-Zahraouy, Abdelilah Benyoussef, Thomas John, Christian Wagner, and Martin Michael Müller
We present a numerical study of the time-dependent motion of a two-dimensional vesicle in a channel under an imposed flow. In a Poiseuille flow the shape of the vesicle depends on the flow strength, the mechanical properties of the membrane, and the width of the channel as reported in the past. This...
[Phys. Rev. E 98, 043111] Published Mon Oct 29, 2018
Author(s): Wenli Di, Zehui Zhang, Lin Li, Kejun Lin, Jun Li, Xiaoguang Li, Bernard P. Binks, Xiaopeng Chen, and Duyang Zang
Experiments shows that with increasing sound intensity, an acoustically levitated drop buckles into a bowl shape and experiences a drastic expansion and closure, leading to the formation of an air bubble. This is attributed to the enhanced suction effect at the film rim due to the occurrence of resonance with sound field.
[Phys. Rev. Fluids 3, 103606] Published Mon Oct 29, 2018
Author(s): N. B. Speirs, M. M. Mansoor, R. C. Hurd, S. I. Sharker, W. G. Robinson, B. J. Williams, and T. T. Truscott
An experimental study shows that splash formation is not reduced when spheres fall into water with a layer of soap bubbles on top. Instead, the bubble layer causes entrained air cavities to form at lower impact velocities. Results also show that the surfactant causes cavity formation to become radius dependent in cases where there is no bubble layer.
[Phys. Rev. Fluids 3, 104004] Published Mon Oct 29, 2018
Author(s): Simon Mendez and Manouk Abkarian
Red blood cells are modeled by an axisymmetric ellipsoid of fixed shape with internal circulation in shear flow without inertia. When accounting for membrane in-plane elasticity the model predicts the expected behaviors of flipping with orbit selection, rolling, frisbeeing, kayaking, and swinging.
[Phys. Rev. Fluids 3, 101101(R)] Published Thu Oct 25, 2018
Author(s): Antoine Piedfert, Benjamin Lalanne, Olivier Masbernat, and Frédéric Risso
Shape-oscillating droplets rising in a liquid are simulated with insoluble surfactants adsorbed at their interface. Conditions are reported in which the average surface tension gradient induces a significant decrease of the rise velocity but does not impact the oscillation dynamics.
[Phys. Rev. Fluids 3, 103605] Published Thu Oct 25, 2018
Large-eddy simulations of turbulent thermal convection using renormalized viscosity and thermal diffusivity
Author(s): Sumit Vashishtha, Mahendra K. Verma, and Roshan Samuel
In this paper we employ renormalized viscosity and thermal diffusivity to construct a subgrid-scale model for large eddy simulation (LES) of turbulent thermal convection. For LES, we add νren∝Πu1/3(π/Δ)−4/3 to the kinematic viscosity; here Πu is the turbulent kinetic energy flux, and Δ is the grid s...
[Phys. Rev. E 98, 043109] Published Wed Oct 24, 2018
Author(s): Adnan Morshed, Prashanta Dutta, Mohammad Robiul Hossan, and Robert Dillon
The electrodeformation of a bio-vesicle suspended in liquid media depends on the conductivity ratio of fluid and vesicle, applied electric field, membrane capacitive charging, and vesicle initial shape. Our theoretical study provides important insights on this complex fluid-structure interaction.
[Phys. Rev. Fluids 3, 103702] Published Wed Oct 24, 2018
Author(s): Shen Liang, Wang Chaohui, and Hu Qiao
In this paper, the theory for acoustic radiation force exerted by standing surface acoustic waves (SSAWs) is extended to a compressible sphere in inviscid fluids. The conventional theory, developed in plane standing waves, fails to predict the radiation force incident on particles in the SSAW. Our e...
[Phys. Rev. E 98, 043108] Published Tue Oct 23, 2018
Author(s): Jonasz Słomka, Alex Townsend, and Jörn Dunkel
Simulations predict that a pendulum immersed in an active fluid oscillates faster than in a passive fluid due to a reduction of the fluid inertia. The decrease in inertia is mediated by topological defects in the stress field, which can effectively decouple the bulk flow dynamics from the pendulum.
[Phys. Rev. Fluids 3, 103304] Published Mon Oct 22, 2018
Author(s): Dileep Mampallil, Meenakshi Sharma, Ashwini Sen, and Shubham Sinha
Drying of colloidal drops on solid surfaces is the widely known method to form self-assembled patterns. The underlying principle of this method is the phenomenon known as the coffee-ring effect. Here, we report a phenomenon of pattern formation involving not drying but conversely wetting and spreadi...
[Phys. Rev. E 98, 043107] Published Fri Oct 19, 2018
Author(s): Véronique Chireux, Matthieu Protat, Frédéric Risso, Thierry Ondarçuhu, and Philippe Tordjeman
Atomic Force Microscope observations find that two drops of radii 0.7 to 70 micrometers jump to contact when separated by a distance that scales as (HReq/γ)1/3 for small drops and as (H/γ)1/2 for larger drops.
[Phys. Rev. Fluids 3, 102001(R)] Published Fri Oct 19, 2018