Latest papers in fluid mechanics

Energy transfer in turbulence under rotation

Physical Review Fluids - Wed, 03/21/2018 - 10:00

Author(s): Michele Buzzicotti, Hussein Aluie, Luca Biferale, and Moritz Linkmann

The formation of intense quasi-2D cyclones characterizes the large-scale dynamics of any turbulent flow under strong rotation. A numerical study shows how 2D and 3D (homochiral) interactions cooperate for the inverse energy cascade.


[Phys. Rev. Fluids 3, 034802] Published Wed Mar 21, 2018

Universal entrainment mechanism controls contact times with motile cells

Physical Review Fluids - Tue, 03/20/2018 - 10:00

Author(s): Arnold J. T. M. Mathijssen, Raphaël Jeanneret, and Marco Polin

Cell interactions from predation to infection depend on direct contact and its duration. Experiments, simulations, and modeling show that for microswimmers contact is regulated by a competition between advection and diffusion akin to a generalized Taylor-dispersion phenomenon.


[Phys. Rev. Fluids 3, 033103] Published Tue Mar 20, 2018

Liquid phase stabilization versus bubble formation at a nanoscale curved interface

Physical Review E - Mon, 03/19/2018 - 10:00

Author(s): Jarrod Schiffbauer and Tengfei Luo

We investigate the nature of vapor bubble formation near a nanoscale-curved convex liquid-solid interface using two models: an equilibrium Gibbs model for homogenous nucleation, and a nonequilibrium dynamic van der Waals–diffuse-interface model for phase change in an initially cool liquid. Vapor bub...


[Phys. Rev. E 97, 033106] Published Mon Mar 19, 2018

Enhancement of the water flow velocity through carbon nanotubes resulting from the radius dependence of the friction due to electron excitations

Physical Review E - Mon, 03/19/2018 - 10:00

Author(s): J. B. Sokoloff

Secchi et al. [Nature (London) 537, 210 (2016)] observed a large enhancement of the permeability and slip length in carbon nanotubes when the tube radius is of the order of 15 nm, but not in boron nitride nanotubes. It will be pointed out that none of the parameters that appear in the usual molecula...


[Phys. Rev. E 97, 033107] Published Mon Mar 19, 2018

Swimming performance and unique wake topology of the sea hare (<i>Aplysia</i>)

Physical Review Fluids - Fri, 03/16/2018 - 10:00

Author(s): Zhuoyu Zhou and Rajat Mittal

The Aplysia, also known as ’sea hare’, is a marine mollusc that swims via large-amplitude flapping. With flow simulations we find a unique pattern in its wake of three vortex ring-like structures which overcome body drag. Swimming performance, however, appears to lag behind that of related species.


[Phys. Rev. Fluids 3, 033102] Published Fri Mar 16, 2018

Two-phase continuum theory for windblown sand

Physical Review Fluids - Fri, 03/16/2018 - 10:00

Author(s): James T. Jenkins and Alexandre Valance

A two-phase continuum theory is derived for grains that collide with and jump above a bed of sand while accelerated by a turbulent wind. The resulting system of equations and boundary conditions for unsteady, uniform and steady, nonuniform flows is solved to determine saturation times and lengths.


[Phys. Rev. Fluids 3, 034305] Published Fri Mar 16, 2018

Fluid particles only separate exponentially in the dissipation range of turbulence after extremely long times

Physical Review Fluids - Fri, 03/16/2018 - 10:00

Author(s): Rohit Dhariwal and Andrew D. Bragg

While it is usually assumed that fluid particles separate exponentially in the dissipation range, this need not be true and the evidence for it is controversial. A re-examination of this old problem shows that fluid particles do indeed separate exponentially but only after extremely long times.


[Phys. Rev. Fluids 3, 034604] Published Fri Mar 16, 2018

Technique for forcing high Reynolds number isotropic turbulence in physical space

Physical Review Fluids - Fri, 03/16/2018 - 10:00

Author(s): John A. Palmore, Jr. and Olivier Desjardins

Linear forcing is commonly used to simulate isotropic turbulence in physical space. Here we modify the forcing term to act on a low-pass filtered velocity field and obtain a 60% increase of the Taylor microscale Reynolds number on the same mesh. An extension is also made to scalar mixing.


[Phys. Rev. Fluids 3, 034605] Published Fri Mar 16, 2018

Experimental examination of vorticity stripping from a wing-tip vortex in free-stream turbulence

Physical Review Fluids - Fri, 03/16/2018 - 10:00

Author(s): Hari C. Ghimire and Sean C. C. Bailey

Circulation loss from a vortex immersed in turbulent surroundings occurs in a nondiffusive manner. Experiments are used to connect the circulation loss to instantaneous instances of vorticity stripping from the vortex core.


[Phys. Rev. Fluids 3, 034702] Published Fri Mar 16, 2018

Non-self-similar viscous gravity currents

Physical Review Fluids - Thu, 03/15/2018 - 10:00

Author(s): Bruce R. Sutherland, Kristen Cote, Youn Sub (Dominic) Hong, Luke Steverango, and Chris Surma

Lock-release experiments of viscous gravity currents (VGC) of glycerol released in water find different dynamics from air release. The current advance is nearly constant, then nearly halts as the head flattens, in contrast to known self-similar VGC where the front advances as a 1/5 power of time.


[Phys. Rev. Fluids 3, 034101] Published Thu Mar 15, 2018

Clustering and entrainment effects on the evaporation of dilute droplets in a turbulent jet

Physical Review Fluids - Thu, 03/15/2018 - 10:00

Author(s): Federico Dalla Barba and Francesco Picano

An investigation of the evaporation of dilute droplets within a turbulent spatial-developing jet via direct numerical simulation is presented. A strong droplet preferential segregation is found, which affects the overall vaporization process and induces a wide spreading of the droplet-size spectrum.


[Phys. Rev. Fluids 3, 034304] Published Thu Mar 15, 2018

Shape dependent phoretic propulsion of slender active particles

Physical Review Fluids - Wed, 03/14/2018 - 10:00

Author(s): Y. Ibrahim, R. Golestanian, and T. B. Liverpool

A study of the swimming speed of rodlike self-propelled colloids driven by reactions on their surfaces finds that even for very thin swimmers, cylinders are not the same as ellipsoids with the same aspect ratio. Cylinders swim faster.


[Phys. Rev. Fluids 3, 033101] Published Wed Mar 14, 2018

Experimental observations of the three-dimensional wake structures and dynamics generated by a rigid, bioinspired pitching panel

Physical Review Fluids - Wed, 03/14/2018 - 10:00

Author(s): Justin T. King, Rajeev Kumar, and Melissa A. Green

The wake created by a trapezoidal pitching panel displays a variety of dynamics and behaviors. Results show that a chain of highly three-dimensional, alternating vortex rings is shed from the trailing edge. These rings interact with each other in a manner that is dependent on Strouhal number.


[Phys. Rev. Fluids 3, 034701] Published Wed Mar 14, 2018

Bursting dynamics of viscous film without circular symmetry: The effect of confinement

Physical Review Fluids - Tue, 03/13/2018 - 10:00

Author(s): Mayuko Murano and Ko Okumura

Experimental observations of bubbles bursting between two confining plates find a constant speed of the rim and a tip that does not grow. The dynamics is governed by surface energy transformed into viscous dissipation. Left and right tip shapes look different due to a difference in focal point.


[Phys. Rev. Fluids 3, 031601(R)] Published Tue Mar 13, 2018

Resistive-force theory for mesh-like superhydrophobic surfaces

Physical Review Fluids - Tue, 03/13/2018 - 10:00

Author(s): Ory Schnitzer and Ehud Yariv

A simple leading-order approximation for the slip-length tensor of an arbitrary mesh geometry is obtained in the limit of small solid-fraction of the mesh.


[Phys. Rev. Fluids 3, 032201(R)] Published Tue Mar 13, 2018

Interactions between vortex tubes and magnetic-flux rings at high kinetic and magnetic Reynolds numbers

Physical Review Fluids - Tue, 03/13/2018 - 10:00

Author(s): Demosthenes Kivotides

Calculations of interactions between vortex tubes and magnetic rings at high kinetic and magnetic Reynolds numbers indicate that when the Lorentz force dominates plasma inertia there is significant new structure generation that results in similar vorticity and magnetic structure morphologies.


[Phys. Rev. Fluids 3, 033701] Published Tue Mar 13, 2018

Relation between boundary slip mechanisms and waterlike fluid behavior

Physical Review E - Mon, 03/12/2018 - 10:00

Author(s): Patricia Ternes, Evy Salcedo, and Marcia C. Barbosa

The slip of a fluid layer in contact with a solid confining surface is investigated for different temperatures and densities using molecular dynamic simulations. We show that for an anomalous waterlike fluid the slip goes as follows: for low levels of shear, defect slip appears and is related to the...


[Phys. Rev. E 97, 033104] Published Mon Mar 12, 2018

Modeling thermal inkjet and cell printing process using modified pseudopotential and thermal lattice Boltzmann methods

Physical Review E - Mon, 03/12/2018 - 10:00

Author(s): Salman Sohrabi and Yaling Liu

Pseudopotential lattice Boltzmann methods (LBMs) can simulate a phase transition in high-density ratio multiphase flow systems. If coupled with thermal LBMs through equation of state, they can be used to study instantaneous phase transition phenomena with a high-temperature gradient where only one s...


[Phys. Rev. E 97, 033105] Published Mon Mar 12, 2018

Effect of synthetic jet modulation schemes on the reduction of a laminar separation bubble

Physical Review Fluids - Mon, 03/12/2018 - 10:00

Author(s): J. H. Seo, F. Cadieux, R. Mittal, E. Deem, and L. Cattafesta

The response of a laminar separation bubble to synthetic jet forcing with various modulation schemes is numerically investigated. The study suggests that the effectiveness of synthetic jet-based flow control could be improved by carefully designing the spectral content of the modulation scheme.


[Phys. Rev. Fluids 3, 033901] Published Mon Mar 12, 2018

Single-particle dispersion in stably stratified turbulence

Physical Review Fluids - Mon, 03/12/2018 - 10:00

Author(s): N. E. Sujovolsky, P. D. Mininni, and M. P. Rast

We develop a model for particle dispersion observed in stably stratified flows, such as in the ocean and the nocturnal atmosphere, where turbulence is very efficient at mixing and diffusing transported quantities. The model opens new efficient paths for statistical prediction of particle dispersion.


[Phys. Rev. Fluids 3, 034603] Published Mon Mar 12, 2018

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