Latest papers in fluid mechanics

Irreversibility inversions in two-dimensional turbulence

Physical Review Fluids - Mon, 02/12/2018 - 10:00

Author(s): Andrew D. Bragg, Filippo De Lillo, and Guido Boffetta

An analysis shows that in 2D turbulence the nature of the irreversibility of two-particle dispersion inverts when the particle inertia exceeds a certain threshold. The results also imply that in turbulent flows with an inverse energy flux, inertial particle-pairs may yet exhibit a downscale flux of energy.

[Phys. Rev. Fluids 3, 024302] Published Mon Feb 12, 2018

Experimental test of the crossover between the inertial and the dissipative range in a turbulent swirling flow

Physical Review Fluids - Fri, 02/09/2018 - 10:00

Author(s): Paul Debue, Denis Kuzzay, Ewe-Wei Saw, François Daviaud, Bérengère Dubrulle, Léonie Canet, Vincent Rossetto, and Nicolás Wschebor

A crossover from a Kolmogorov decay of two decades in the inertial range to a stretched exponential in the dissipative range is unveiled in the experimental spatial energy spectrum of a turbulent swirling flow, as recently predicted based on nonperturbative renormalization group theory.

[Phys. Rev. Fluids 3, 024602] Published Fri Feb 09, 2018

Marangoni-flow-induced partial coalescence of a droplet on a liquid/air interface

Physical Review Fluids - Thu, 02/08/2018 - 10:00

Author(s): Kai Sun, Peng Zhang, Zhizhao Che, and Tianyou Wang

Numerical simulations show that the coalescence of a droplet on a liquid-air interface of lower surface tension manifests the nonmonotonic phenomena of emergence, disappearance, and re-emergence of “partial coalescence” with increasing surface-tension difference.

[Phys. Rev. Fluids 3, 023602] Published Thu Feb 08, 2018

Direct numerical simulation of a compressible boundary-layer flow past an isolated three-dimensional hump in a high-speed subsonic regime

Physical Review Fluids - Thu, 02/08/2018 - 10:00

Author(s): D. De Grazia, D. Moxey, S. J. Sherwin, M. A. Kravtsova, and A. I. Ruban

The boundary-layer separation produced by a small hump in a high-speed subsonic regime typical of civil aviation is studied. Different heights of the hump are considered, with the larger resulting in a fully nonlinear regime and the formation of a pair of streamwise counterrotating vortices.

[Phys. Rev. Fluids 3, 024101] Published Thu Feb 08, 2018

Clogging in constricted suspension flows

Physical Review E - Wed, 02/07/2018 - 10:00

Author(s): Alvaro Marin, Henri Lhuissier, Massimiliano Rossi, and Christian J. Kähler

The flow of a charged-stabilized suspension through a single constricted channel is studied experimentally by tracking the particles individually. Surprisingly, the behavior is found to be qualitatively similar to that of inertial dry granular systems: For small values of the neck-to-particle size r...

[Phys. Rev. E 97, 021102(R)] Published Wed Feb 07, 2018

Viscous entrainment on hairy surfaces

Physical Review Fluids - Wed, 02/07/2018 - 10:00

Author(s): Alice Nasto, P.-T. Brun, and A. E. Hosoi

Inspired by nectar-drinking bats, an experimental and theoretical study investigates viscous entrainment in hairy textures. The trapped liquid is modeled using a Darcy-Brinkmann-like approach and the drainage flow solution is derived. The results reveal an optimal hair density to maximize fluid uptake.

[Phys. Rev. Fluids 3, 024002] Published Wed Feb 07, 2018

Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops

Physical Review E - Tue, 02/06/2018 - 10:00

Author(s): Fan Yang, Owen Cruikshank, Weilue He, Alex Kostinski, and Raymond A. Shaw

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the ...

[Phys. Rev. E 97, 023103] Published Tue Feb 06, 2018

Breakup dynamics of toroidal droplets in shear-thinning fluids

Physical Review E - Mon, 02/05/2018 - 10:00

Author(s): Alexandros A. Fragkopoulos, Ekapop Pairam, Luka Marinkovic, and Alberto Fernández-Nieves

We use toroidal droplets to study the breakup dynamics of a Newtonian liquid jet in the presence of rheologically nonlinear materials. We find that the droplets resist breakup for times that are longer than those in the presence of Newtonian liquids. More importantly, we show that our experiments ca...

[Phys. Rev. E 97, 021101(R)] Published Mon Feb 05, 2018

Three-bead steering microswimmers

Physical Review E - Mon, 02/05/2018 - 10:00

Author(s): Mohd Suhail Rizvi, Alexander Farutin, and Chaouqi Misbah

The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with ...

[Phys. Rev. E 97, 023102] Published Mon Feb 05, 2018

Comment on “Effect of liquid temperature on sonoluminescence”

Physical Review E - Mon, 02/05/2018 - 10:00

Author(s): Yuri A. Pishchalnikov

It has been suggested that bubble-wall velocities cannot exceed the sound speed in the liquid at the bubble wall [K. Yasui, Phys. Rev. E 64, 016310 (2001).]. Here we show that this upper bound was derived omitting the partial derivatives with respect to time, i.e., assuming that the flow was in the ...

[Phys. Rev. E 97, 027101] Published Mon Feb 05, 2018

Gravity-driven, dry granular flows over a loose bed in stationary and homogeneous conditions

Physical Review Fluids - Mon, 02/05/2018 - 10:00

Author(s): Sabrina Meninno, Aronne Armanini, and Michele Larcher

Vertical and transversal structures clearly change as interparticle interactions become more collisional. Bottom and lateral confinement prove to be decisive for friction and energy dissipation as experimental evidence shows.

[Phys. Rev. Fluids 3, 024301] Published Mon Feb 05, 2018

Influence of outer medium viscosity on the motion of rolling droplets down an incline

Physical Review Fluids - Fri, 02/02/2018 - 10:00

Author(s): Muhammad Rizwanur Rahman and Prashant R. Waghmare

When droplets roll down inclines, their velocities are affected by their characteristic size. Larger droplets will travel faster unless they’re too big. Droplets larger than a “critical” size travel more slowly. An investigation shows that this critical size is determined by the viscosity of the surrounding medium.

[Phys. Rev. Fluids 3, 023601] Published Fri Feb 02, 2018

Experimental study of the flow in the wake of a stationary sphere immersed in a turbulent boundary layer

Physical Review Fluids - Fri, 02/02/2018 - 10:00

Author(s): René van Hout, Jerke Eisma, Gerrit E. Elsinga, and Jerry Westerweel

3D flow measurements in the wake of a sphere positioned close to the wall in a turbulent boundary layer indicate that the wake deflects away from the wall as a result of induced motion of preferentially aligned, shed “hairpin” vortices. This is increasingly so with decreasing sphere-wall gap.

[Phys. Rev. Fluids 3, 024601] Published Fri Feb 02, 2018

Publisher's Note: Turbulence intermittency in a multiple-time-scale Navier-Stokes-based reduced model [Phys. Rev. Fluids <b>2</b>, 072601(R) (2017)]

Physical Review Fluids - Fri, 02/02/2018 - 10:00

Author(s): Perry L. Johnson and Charles Meneveau

[Phys. Rev. Fluids 3, 029901] Published Fri Feb 02, 2018

Mixing and pumping by pairs of helices in a viscous fluid

Physical Review E - Thu, 02/01/2018 - 10:00

Author(s): Amy Buchmann, Lisa J. Fauci, Karin Leiderman, Eva Strawbridge, and Longhua Zhao

Here, we study the fluid dynamics of a pair of rigid helices rotating at a constant velocity, tethered at their bases, in a viscous fluid. Our computations use a regularized Stokeslet framework, both with and without a bounding plane, so we are able to discern precisely what flow features are unacco...

[Phys. Rev. E 97, 023101] Published Thu Feb 01, 2018

Instability and dynamics of volatile thin films

Physical Review Fluids - Thu, 02/01/2018 - 10:00

Author(s): Hangjie Ji and Thomas P. Witelski

Volatile viscous fluids on partially-wetting solid substrates can exhibit interesting dynamics and interfacial instabilities. A study of vapor condensation and fluid evaporation in a one-sided lubrication model incorporating surface tension, intermolecular effects, and evaporative fluxes is presented.

[Phys. Rev. Fluids 3, 024001] Published Thu Feb 01, 2018

Editorial: The 2017 François Naftali Frenkiel Award for Fluid Mechanics

Physical Review Fluids - Wed, 01/31/2018 - 10:00

Author(s): John Kim and Gary Leal

[Phys. Rev. Fluids 3, 010003] Published Wed Jan 31, 2018

Two-dimensional dynamics of elasto-inertial turbulence and its role in polymer drag reduction

Physical Review Fluids - Wed, 01/31/2018 - 10:00

Author(s): S. Sid, V. E. Terrapon, and Y. Dubief

Direct numerical simulations of a FENE-P fluid in both two- and three-dimensional straight periodic channels find that elasto-inertial turbulence is fundementally two-dimensional. The spurious effect of artificial diffusion of the polymer is demonstrated.

[Phys. Rev. Fluids 3, 011301(R)] Published Wed Jan 31, 2018

Extended localized structures and the onset of turbulence in channel flow

Physical Review Fluids - Wed, 01/31/2018 - 10:00

Author(s): J. J. Tao, Bruno Eckhardt, and X. M. Xiong

Numerical simulations of plane-Poiseuille flow find a state of sparse but persistent oblique turbulent bands in a Reynolds number range between about 660 and 800, which is below the anticipated directed percolation transition.

[Phys. Rev. Fluids 3, 011902(R)] Published Wed Jan 31, 2018

Promenading pairs of walking droplets: Dynamics and stability

Physical Review Fluids - Wed, 01/31/2018 - 10:00

Author(s): Juncal Arbelaiz, Anand U. Oza, and John W. M. Bush

An integrated experimental and theoretical investigation of the promenade mode, a bound state formed by a pair of droplets walking side by side on the surface of a vibrating fluid bath, highlights the role of bouncing phase adaptation in stabilizing the promenade mode.

[Phys. Rev. Fluids 3, 013604] Published Wed Jan 31, 2018


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