Latest papers in fluid mechanics

Enhanced slip properties of lubricant-infused grooves

Physical Review E - Tue, 09/04/2018 - 11:00

Author(s): Evgeny S. Asmolov, Tatiana V. Nizkaya, and Olga I. Vinogradova

We ascertain the enhanced slip properties for a liquid flow over lubricant-infused unidirectional surfaces. This situation reflects many practical settings involving liquid flows past superhydrophobic grooves filled with gas, or past grooves infused with another, immiscible, liquid of smaller or equ...


[Phys. Rev. E 98, 033103] Published Tue Sep 04, 2018

Flow of wormlike micellar fluids around a sharp bend: Effects of branching and shear-banding

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Yiran Zhang, Hadi Mohammadigoushki, Margaret Y. Hwang, and Susan J. Muller

Flow transitions in wormlike micelle solutions flowing around a microfluidic 90° bend are studied. Shear-banding properties of the solution correlate with the form of secondary flow, while the micelle morphology (linear vs branched) has little effect on the flow behavior.


[Phys. Rev. Fluids 3, 093301] Published Tue Sep 04, 2018

Interaction of multiple drops and formation of toroidal-spiral particles

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Paola Leon Plata, Ying Liu, and Ludwig C. Nitsche

During sedimentation in a miscible, viscous liquid, polymeric drops self-assemble into a toroidal-spiral structure, which can be solidified by photoinitiated cross-linking. With a suitable arrangement three drops can be encapsulated, possibly enabling controlled release of a therapeutic drug cocktail.


[Phys. Rev. Fluids 3, 093601] Published Tue Sep 04, 2018

Scale dependence of kinetic helicity and selection of the axial dipole in rapidly rotating dynamos

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Binod Sreenivasan and Subhajit Kar

To understand why the magnetic fields of many planets are axial dipoles, the evolution in time of a seed magnetic field is studied using a dynamo model. The field is shown to excite helical convection, and the timescale for the growth in convection matches that for dipole formation.


[Phys. Rev. Fluids 3, 093801] Published Tue Sep 04, 2018

Heating-induced drag reduction in relative movement of parallel plates

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): J. M. Floryan, S. Shadman, and M. Z. Hossain

A new analysis shows that the force required to maintain the relative movement of parallel plates is significantly reduced when these plates are heated in a spatially nonuniform manner.


[Phys. Rev. Fluids 3, 094101] Published Tue Sep 04, 2018

Inviscid simulations of expansion waves propagating into structured particle beds at low volume fractions

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Goran Marjanovic, Jason Hackl, Mrugesh Shringarpure, Subramanian Annamalai, Thomas L. Jackson, and S. Balachandar

We perform fully resolved simulations of expansion waves propagating into particle beds of varying volume fractions using the discontinuous Galerkin spectral element method. We validate state-of-the-art drag models and predict the final state of the particle bed using isentropic flow relations.


[Phys. Rev. Fluids 3, 094301] Published Tue Sep 04, 2018

Finite-size Lagrangian coherent structures in thermocapillary liquid bridges

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Francesco Romanò and Hendrik C. Kuhlmann

A numerical investigation shows that finite-size Lagrangian coherent structures result from bulk transport near Kolmogorov-Arnold-Moser tori and a dissipative effect that finite-size particles experience near the free surface.


[Phys. Rev. Fluids 3, 094302] Published Tue Sep 04, 2018

Intermittency enhancement in quantum turbulence in superfluid $^{4}\mathrm{He}$

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Emil Varga, Jian Gao, Wei Guo, and Ladislav Skrbek

Intermittency of quasiclassical quantum turbulence in superfluid 4He is experimentally found to be temperature dependent and enhanced for a range of temperatures compared to classical turbulence, in contrast with nearly flow-independent intermittency of turbulence in classical fluids.


[Phys. Rev. Fluids 3, 094601] Published Tue Sep 04, 2018

Theoretical framework to analyze the combined effect of surface tension and viscosity on the damping rate of sloshing waves

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Francesco Viola and François Gallaire

A dynamic meniscus affects viscous dissipation of oscillating contact lines. A theoretical proposal, marrying viscous sloshing dynamics and a realistic contact line model including contact angle hysteresis, finds that both the wave damping rate and frequency increase at small amplitude.


[Phys. Rev. Fluids 3, 094801] Published Tue Sep 04, 2018

Spectrum of shallow water gravity waves generated by confined two-dimensional turbulence

Physical Review Fluids - Tue, 09/04/2018 - 11:00

Author(s): Claudio Falcón and Edgar Knobloch

Two-dimensional turbulence can generate shallow water waves. These waves carry information about the structure of their turbulent source. A theoretical calculation of the wave spectrum is proposed, which may lead to an insightful way to characterize turbulence.


[Phys. Rev. Fluids 3, 094802] Published Tue Sep 04, 2018

Machine-learning inference of fluid variables from data using reservoir computing

Physical Review E - Fri, 08/31/2018 - 11:00

Author(s): Kengo Nakai and Yoshitaka Saiki

We infer both microscopic and macroscopic behaviors of a three-dimensional chaotic fluid flow using reservoir computing. In our procedure of the inference, we assume no prior knowledge of a physical process of a fluid flow except that its behavior is complex but deterministic. We present two ways of...


[Phys. Rev. E 98, 023111] Published Fri Aug 31, 2018

Energy contributions by inner and outer motions in turbulent channel flows

Physical Review Fluids - Fri, 08/31/2018 - 11:00

Author(s): Ruifeng Hu and Xiaojing Zheng

In a new study, the critical Reynolds number for the emergence of outer motions in turbulent channel flows is determined to be Reτ≈110. The growing significance of outer motions is obtained by subtracting the inner contributions from the total at low to moderate Reynolds numbers.


[Phys. Rev. Fluids 3, 084607] Published Fri Aug 31, 2018

Rayleigh-Taylor instability under a spherical substrate

Physical Review Fluids - Thu, 08/30/2018 - 11:00

Author(s): Gioele Balestra, David Minh-Phuc Nguyen, and François Gallaire

The Rayleigh-Taylor instability of a thin viscous film coating the inside of a spherical substrate is studied. The instability properties are investigated by performing a linear optimal transient growth analysis. The pattern formation is further analyzed using nonlinear numerical simulations.


[Phys. Rev. Fluids 3, 084005] Published Thu Aug 30, 2018

Geometric state function for two-fluid flow in porous media

Physical Review Fluids - Thu, 08/30/2018 - 11:00

Author(s): James E. McClure, Ryan T. Armstrong, Mark A. Berrill, Steffen Schlüter, Steffen Berg, William G. Gray, and Cass T. Miller

It is shown that the geometric state of fluids within porous media can be expressed in terms of a relationship that links the fluid volume, surface area, mean curvature, and Euler characteristic. The relationship is able to accurately model complex changes in fluid connectivity and structure.


[Phys. Rev. Fluids 3, 084306] Published Thu Aug 30, 2018

Direct numerical simulations of multifluid flows in a vertical channel undergoing topology changes

Physical Review Fluids - Thu, 08/30/2018 - 11:00

Author(s): Jiacai Lu and Gretar Tryggvason

Multifluid flows with changes in the topology of the interface separating the different fluids, in a turbulent vertical channel, are examined using direct numerical simulations. The results show how different surface tension changes the evolution of the flow and the interface topology.


[Phys. Rev. Fluids 3, 084401] Published Thu Aug 30, 2018

Reversals in infinite-Prandtl-number Rayleigh-Bénard convection

Physical Review E - Wed, 08/29/2018 - 11:00

Author(s): Ambrish Pandey, Mahendra K. Verma, and Mustansir Barma

Using direct numerical simulations, we study the statistical properties of reversals in two-dimensional Rayleigh-Bénard convection for infinite Prandtl number. We find that the large-scale circulation reverses irregularly, with the waiting time between two consecutive genuine reversals exhibiting a ...


[Phys. Rev. E 98, 023109] Published Wed Aug 29, 2018

Collapse of generalized Euler and surface quasigeostrophic point vortices

Physical Review E - Wed, 08/29/2018 - 11:00

Author(s): Gualtiero Badin and Anna M. Barry

Point-vortex models are presented for the generalized Euler equations, which are characterized by a fractional Laplacian relation between the active scalar and the stream function. Special focus is given to the case of the surface quasigeostrophic (SQG) equations, for which the existence of finite-t...


[Phys. Rev. E 98, 023110] Published Wed Aug 29, 2018

Dynamics of viscoelastic filaments based on Onsager principle

Physical Review Fluids - Wed, 08/29/2018 - 11:00

Author(s): Jiajia Zhou and Masao Doi

Exponential thinning of a viscoelastic filament is analyzed using the Onsager variational principle.


[Phys. Rev. Fluids 3, 084004] Published Wed Aug 29, 2018

Wavelet multiresolution analysis of particle-laden turbulence

Physical Review Fluids - Wed, 08/29/2018 - 11:00

Author(s): Maxime Bassenne, Parviz Moin, and Javier Urzay

The preferential concentration of inertial particles in isotropic turbulence is studied using wavelets, enabling the joint scale-space analysis of the flow field of the carrier phase, the concentration field of the dispersed phase, and interphase conditioned statistics.


[Phys. Rev. Fluids 3, 084304] Published Wed Aug 29, 2018

Heat transfer from an array of resolved particles in turbulent flow

Physical Review Fluids - Wed, 08/29/2018 - 11:00

Author(s): Yayun Wang and Andrea Prosperetti

Resolved simulations of turbulent flow past a fixed planar array of cold particles show the fundamental differences between velocity and temperature fields, cast light on the limitations of the point particle model and illustrate the mechanism by which turbulence disrupts the thermal wakes.


[Phys. Rev. Fluids 3, 084305] Published Wed Aug 29, 2018

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