Latest papers in fluid mechanics

Shear fronts in shear-thickening suspensions

Physical Review Fluids - Wed, 07/11/2018 - 11:00

Author(s): Endao Han, Matthieu Wyart, Ivo R. Peters, and Heinrich M. Jaeger

Snapshot of a propagating shear front that transforms a dense suspension from a fluid into a jammed, solid-like state. A comprehensive description of this transformation is developed, which links the transient dynamics to parameters obtainable from steady-state rheology.


[Phys. Rev. Fluids 3, 073301] Published Wed Jul 11, 2018

Resolvent analysis of separated and attached flows around an airfoil at transitional Reynolds number

Physical Review Fluids - Wed, 07/11/2018 - 11:00

Author(s): Nikitas Thomareis and George Papadakis

Cross-stream component of the optimal response at the natural shear layer frequency (solid black line: displacement thickness of the boundary layer, solid brown line: zero-streamwise mean velocity contour).


[Phys. Rev. Fluids 3, 073901] Published Wed Jul 11, 2018

Minimum size for the top jet drop from a bursting bubble

Physical Review Fluids - Wed, 07/11/2018 - 11:00

Author(s): C. Frederik Brasz, Casey T. Bartlett, Peter L. L. Walls, Elena G. Flynn, Yingxian Estella Yu, and James C. Bird

High-speed imaging experiments and numerical simulations show that the minimum size of drops ejected after bubble bursting is determined by an interplay of viscous and inertial-capillary forces both prior and subsequent to jet formation. Implications for sea spray aerosol generation are discussed.


[Phys. Rev. Fluids 3, 074001] Published Wed Jul 11, 2018

Clogging at pore scale and pressure-induced erosion

Physical Review Fluids - Wed, 07/11/2018 - 11:00

Author(s): R. Jäger, M. Mendoza, and H. J. Herrmann

Using a coupled lattice Boltzmann method/discrete element method model, the clogging of a pore with particles at microscopic scale is studied. We show that erosive bursts occur when the hydraulic pressure exceeds a critical point, which depends on the adhesive forces and the pores’ geometry.


[Phys. Rev. Fluids 3, 074302] Published Wed Jul 11, 2018

Sinuous distortion of vortex surfaces in the lateral growth of turbulent spots

Physical Review Fluids - Wed, 07/11/2018 - 11:00

Author(s): Yaomin Zhao, Shiying Xiong, Yue Yang, and Shiyi Chen

There is a continued debate about the generation mechanism of turbulent spots in boundary-layer transition. We use the vortex-surface field to show that the sinuous distortion of vortex surfaces plays an important role in the rapid lateral growth of turbulent spots.


[Phys. Rev. Fluids 3, 074701] Published Wed Jul 11, 2018

Non-intermittent turbulence: Lagrangian chaos and irreversibility

Physical Review Fluids - Tue, 07/10/2018 - 11:00

Author(s): Samriddhi Sankar Ray

Simulations of Lagrangian turbulence with Fourier components removed (decimation) show no effect on the level of chaos but an emergent time reversality as indicated by the ratio of Lyapunov exponents shown in the figure.


[Phys. Rev. Fluids 3, 072601(R)] Published Tue Jul 10, 2018

External intermittency compensation of dissipation scale distributions in a turbulent boundary layer

Physical Review Fluids - Tue, 07/10/2018 - 11:00

Author(s): Sabah F. H. Alhamdi and Sean C. C. Bailey

We investigate the effect of external intermittency on dissipation scales in turbulent boundary layer flow at Reτ≈1000 using a single hot wire probe for one point longitudinal velocity measurements. We find improved scaling universality by accounting for external intermittency throughout the flow.


[Phys. Rev. Fluids 3, 074601] Published Tue Jul 10, 2018

Physics-informed machine learning approach for augmenting turbulence models: A comprehensive framework

Physical Review Fluids - Tue, 07/10/2018 - 11:00

Author(s): Jin-Long Wu, Heng Xiao, and Eric Paterson

We present a comprehensive framework for augmenting turbulence models with physics-informed machine learning, illustrating a complete workflow from identification of input/output to prediction of mean velocities. The learned model has Galilean invariance and coordinate rotational invariance.


[Phys. Rev. Fluids 3, 074602] Published Tue Jul 10, 2018

Axisymmetric lattice Boltzmann simulation of droplet impact on solid surfaces

Physical Review E - Mon, 07/09/2018 - 11:00

Author(s): Hussein N. Dalgamoni and Xin Yong

Droplet-solid interaction is a ubiquitous fluid phenomenon that underpins a wide range of applications. To further the understanding of this important problem, we use an axisymmetric lattice Boltzmann method (LBM) to model the droplet impact on a solid surface with different wettability. The method ...


[Phys. Rev. E 98, 013102] Published Mon Jul 09, 2018

Electrohydrodynamic interaction, deformation, and coalescence of suspended drop pairs at varied angle of incidence

Physical Review Fluids - Mon, 07/09/2018 - 11:00

Author(s): Qingming Dong and Amalendu Sau

For a pair of suspended leaky drops, the computed drop velocity (u) with varied permittivity-ratio (εin/εout) and two ‘outflow’ outer vortex pairs drive prolate and oblate deformation mechanisms. Two drops diverge for positive ‘u’ and move closer together and coalesce for negative ‘u’.


[Phys. Rev. Fluids 3, 073701] Published Mon Jul 09, 2018

Controlling wetting with electrolytic solutions: Phase-field simulations of a droplet-conductor system

Physical Review E - Thu, 07/05/2018 - 11:00

Author(s): Gaute Linga, Asger Bolet, and Joachim Mathiesen

The wetting properties of immiscible two-phase systems are crucial in applications ranging from laboratory-on-a-chip devices to field-scale oil recovery. It has long been known that effective wetting properties can be altered by the application of an electric field; a phenomenon coined as electrowet...


[Phys. Rev. E 98, 013101] Published Thu Jul 05, 2018

Molecular origin of contact line friction in dynamic wetting

Physical Review Fluids - Thu, 07/05/2018 - 11:00

Author(s): Petter Johansson and Berk Hess

Molecular processes of contact line advancement in dynamic wetting is investigated for no-slip systems using computer simulations. The energy dissipation at the contact line is measured and shown to be large for mesoscopic systems. A model for the dissipation term is proposed.


[Phys. Rev. Fluids 3, 074201] Published Thu Jul 05, 2018

Electrophoretic slip-tuned particle migration in microchannel viscoelastic fluid flows

Physical Review Fluids - Thu, 07/05/2018 - 11:00

Author(s): Di Li and Xiangchun Xuan

Particles migrate towards the center or walls of a rectangular microchannel if they lead or lag a viscoelastic fluid flow due to positive and negative electrophoresis, respectively. This is opposite to a Newtonian fluid. We attribute this to the shear-induced extra lift in a viscoelastic fluid.


[Phys. Rev. Fluids 3, 074202] Published Thu Jul 05, 2018

Dynamics of growth and detachment of an isolated bubble on an inclined surface

Physical Review Fluids - Tue, 07/03/2018 - 11:00

Author(s): M. Lebon, J. Sebilleau, and C. Colin

Experiments on air bubbles nucleated on an inclined plate show the importance of the bubble foot shape. A new expression for the capillary force is proposed to predict the bubble detachment diameter.


[Phys. Rev. Fluids 3, 073602] Published Tue Jul 03, 2018

Rheological response of nonspherical granular flows down an incline

Physical Review Fluids - Tue, 07/03/2018 - 11:00

Author(s): R. C. Hidalgo, B. Szabó, K. Gillemot, T. Börzsönyi, and T. Weinhart

Our discrete element simulations and laboratory experiments revealed that density and friction are well-defined functions of the effective inertial number, which fully captures the effect of grain elongation.


[Phys. Rev. Fluids 3, 074301] Published Tue Jul 03, 2018

Splash of a drop impacting onto a solid substrate wetted by a thin film of another liquid

Physical Review Fluids - Mon, 07/02/2018 - 11:00

Author(s): Hannah M. Kittel, Ilia V. Roisman, and Cameron Tropea

Experiments on single drop impacts on thin films of another liquid are analyzed theoretically over 8 orders of magnitude in viscosity ratio νf/νd. Away from νf≊νd we find that the K-numbers determine the splashing threshold and in that region a modified K-number, which we introduce, is needed.


[Phys. Rev. Fluids 3, 073601] Published Mon Jul 02, 2018

Linear stability analysis of thermoviscous instability in immiscible displacement

Physical Review E - Fri, 06/29/2018 - 11:00

Author(s): Christopher Nilsen

We study the thermoviscous fingering instability problem that develops when an injected fluid is displacing a fluid with different temperature and viscosity in a Hele-Shaw cell or porous medium. Using linear stability theory, we show how the thermal front caused by the different temperature of the i...


[Phys. Rev. E 97, 063112] Published Fri Jun 29, 2018

Hydrodynamic stress correlations in fluid films driven by stochastic surface forcing

Physical Review Fluids - Fri, 06/29/2018 - 11:00

Author(s): Masoud Mohammadi-Arzanagh, Saeed Mahdisoltani, Rudolf Podgornik, and Ali Naji

Driving a planar thin film of a compressible viscous fluid using random surface forcing leads to remarkable fluctuation-induced stresses on the bounding surfaces of the film, exhibiting power-law, or even non-decaying, behaviors as a function of the film thickness.


[Phys. Rev. Fluids 3, 064201] Published Fri Jun 29, 2018

Identifying Faraday rogue wave precursors from surrounding waveform information

Physical Review Fluids - Thu, 06/28/2018 - 11:00

Author(s): Hsiang-Ying Chen, Chun-Yu Liu, and Lin I

Experiments find that rogue wave events for Faraday waves tend to be preceded one period before by a surrounding waveform of high angular average and small variation of wave height.


[Phys. Rev. Fluids 3, 064401] Published Thu Jun 28, 2018

Preferential concentration of noninertial buoyant particles in the ocean mixed layer under free convection

Physical Review Fluids - Thu, 06/28/2018 - 11:00

Author(s): Tomás Chor, Di Yang, Charles Meneveau, and Marcelo Chamecki

A large eddy simulation is used to study the surface patterns of noninertial passive buoyant particles in the ocean mixed layer. A mechanism for preferential concentration that is independent of inertial effects is then identified and quantified as a function of the terminal rise velocity.


[Phys. Rev. Fluids 3, 064501] Published Thu Jun 28, 2018

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