Latest papers in fluid mechanics

Post-pinch-off relaxation of two-dimensional droplets in a Hele-Shaw cell

Physical Review Fluids - Tue, 12/18/2018 - 10:00

Author(s): Dhirendra Tiwari, Lionel Mercury, Marcel Dijkstra, Himanshu Chaudhary, and José Federico Hernández-Sánchez

The relaxation of a liquid drop in a Hele-Shaw cell is observed experimentally and then modeled successfully.


[Phys. Rev. Fluids 3, 124202] Published Tue Dec 18, 2018

Unsteady motion of a long bubble or droplet in a self-rewetting system

Physical Review Fluids - Mon, 12/17/2018 - 10:00

Author(s): B. R. Duffy, S. K. Wilson, J. J. A. Conn, and K. Sefiane

The evolution of the shape (but not the position) of a long bubble or droplet in a self-rewetting system in a nonuniformly heated tube is shown to be driven entirely by Marangoni effects: a wide droplet widens (and ultimately fills the cross section of the tube), whereas a narrow droplet narrows.


[Phys. Rev. Fluids 3, 123603] Published Mon Dec 17, 2018

Hierarchical random additive model for the spanwise and wall-normal velocities in wall-bounded flows at high Reynolds numbers

Physical Review Fluids - Mon, 12/17/2018 - 10:00

Author(s): X. I. A. Yang, R. Baidya, Yu Lv, and I. Marusic

Both the spanwise and the vertical velocity components in high-Reynolds-number wall-bounded flows may be modeled via a random additive process. Evidence shows that a hierarchical, treelike structure exists for the spanwise velocity component.


[Phys. Rev. Fluids 3, 124606] Published Mon Dec 17, 2018

Cascade leading to the emergence of small structures in vortex ring collisions

Physical Review Fluids - Mon, 12/17/2018 - 10:00

Author(s): Ryan McKeown, Rodolfo Ostilla-Mónico, Alain Pumir, Michael P. Brenner, and Shmuel M. Rubinstein

A novel breakdown mechanism is observed during the head-on collision of two vortex rings. The interacting cores locally flatten into extremely thin vortex sheets and split into smaller daughter filaments iteratively over two generations, leading to the rapid emergence of fine-scale vortices.


[Phys. Rev. Fluids 3, 124702] Published Mon Dec 17, 2018

Viscous damping of gravity-capillary waves: Dispersion relations and nonlinear corrections

Physical Review Fluids - Mon, 12/17/2018 - 10:00

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

Relative velocities in bidisperse turbulent aerosols: Simulations and theory

Physical Review E - Thu, 12/13/2018 - 10:00

Author(s): Akshay Bhatnagar, K. Gustavsson, B. Mehlig, and Dhrubaditya Mitra

We perform direct numerical simulations of a bidisperse suspension of heavy spherical particles in forced, homogeneous, and isotropic three-dimensional turbulence. We compute the joint distribution of relative particle distances and longitudinal relative velocities between particles of different ine...


[Phys. Rev. E 98, 063107] Published Thu Dec 13, 2018

Apparent slip and drag reduction for the flow over superhydrophobic and lubricant-impregnated surfaces

Physical Review Fluids - Thu, 12/13/2018 - 10:00

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

Data-assimilated low-order vortex modeling of separated flows

Physical Review Fluids - Thu, 12/13/2018 - 10:00

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

An amplitude equation for surface gravity wave-topography interactions

Physical Review Fluids - Thu, 12/13/2018 - 10:00

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

Role of symmetry in driven propulsion at low Reynolds number

Physical Review E - Wed, 12/12/2018 - 10:00

Author(s): Johannes Sachs, Konstantin I. Morozov, Oded Kenneth, Tian Qiu, Nico Segreto, Peer Fischer, and Alexander M. Leshansky

We theoretically and experimentally investigate low-Reynolds-number propulsion of geometrically achiral planar objects that possess a dipole moment and that are driven by a rotating magnetic field. Symmetry considerations (involving parity P̂ and charge conjugation Ĉ) establish correspondence betwe...


[Phys. Rev. E 98, 063105] Published Wed Dec 12, 2018

Experimental modulation and theoretical simulation of zonal oscillation for electrostatically levitated metallic droplets at high temperatures

Physical Review E - Wed, 12/12/2018 - 10:00

Author(s): H. P. Wang, M. X. Li, P. F. Zou, X. Cai, L. Hu, and B. Wei

The second- and third-order zonal oscillations of metallic droplets at high temperatures beyond 2000 K were experimentally achieved by electrostatic levitation. To quantitatively describe the suspension stability of different metallic droplets, a stability factor model was proposed as a function of ...


[Phys. Rev. E 98, 063106] Published Wed Dec 12, 2018

Childhood of turbulent spots in a shear flow

Physical Review Fluids - Wed, 12/12/2018 - 10:00

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

Physical Review Fluids - Wed, 12/12/2018 - 10:00

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

Nonequilibrium solid-solid phase transition in a lattice of liquid jets

Physical Review E - Tue, 12/11/2018 - 10:00

Author(s): Fabrizio Croccolo, Stefano Castellini, Frank Scheffold, and Alberto Vailati

Solid-solid phase transitions are commonly encountered at the atomic scale in alloys and in superatomic mesoscopic systems of colloidal particles. Here we investigate a solid-solid phase transition occurring at the macroscopic scale between lattices of liquid jets with different symmetries generated...


[Phys. Rev. E 98, 063104] Published Tue Dec 11, 2018

Optimal design of deterministic lateral displacement device for viscosity-contrast-based cell sorting

Physical Review Fluids - Tue, 12/11/2018 - 10:00

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

Electromagnetic field orientation and characteristics governed hydrodynamics within pendent droplets

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

Author(s): Purbarun Dhar, Vivek Jaiswal, and A. R. Harikrishnan

This article reports the dominant governing role played by the direction of electric and magnetic fields on the internal advection pattern and strength within salt solution pendent droplets. The literature shows that solutal advection drives circulation cells within salt based droplets, even in the ...


[Phys. Rev. E 98, 063103] Published Mon Dec 10, 2018

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

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

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

Assessment of continuum breakdown for chemically reacting wake flows

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

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

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

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

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