Physical Review Fluids

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Recent articles in Physical Review Fluids
Updated: 2 days 20 hours ago

Boiling regimes of impacting drops on a heated substrate under reduced pressure

Wed, 05/02/2018 - 11:00

Author(s): Michiel A. J. van Limbeek, Paul B. J. Hoefnagels, Minori Shirota, Chao Sun, and Detlef Lohse

Reduction of the ambient pressure changes the boiling behavior of impacting ethanol drops on a heated substrate as observed by contact area measurements (insets). With decreasing ambient pressure, we find a widening of the transition boiling regime, while TLeidenfrost stays roughly constant.

[Phys. Rev. Fluids 3, 053601] Published Wed May 02, 2018

Flow produced by a free-moving floating magnet driven electromagnetically

Mon, 04/30/2018 - 11:00

Author(s): Saúl Piedra, Joel Román, Aldo Figueroa, and Sergio Cuevas

In an experimental and numerical study, a magnet floating in a thin electrolyte layer is dragged and accelerated by a vortex dipole generated by a Lorentz force. Vortex shedding appears when a sufficiently high electric current is applied, promoting a zigzag magnet motion.

[Phys. Rev. Fluids 3, 043702] Published Mon Apr 30, 2018

Fluid flow in a porous medium with transverse permeability discontinuity

Mon, 04/30/2018 - 11:00

Author(s): Galina E. Pavlovskaya, Thomas Meersmann, Chunyu Jin, and Sean P. Rigby

Magnetic resonance imaging is used to map out velocity fields during fluid flow in a clear channel coupled to a permeable wall. The maps are compared to lattice Boltzmann modeling to demonstrate that the velocity fields can be simulated without analytical expression of the boundary velocities.

[Phys. Rev. Fluids 3, 044102] Published Mon Apr 30, 2018

Hybrid finite-difference/lattice Boltzmann simulations of microchannel and nanochannel acoustic streaming driven by surface acoustic waves

Mon, 04/30/2018 - 11:00

Author(s): Ming K. Tan and Leslie Y. Yeo

The acoustic streaming flow in microchannels and nanochannels caused by complex fluid-structural coupling due to surface acoustic waves is studied using a hybrid continuum and mesoscale numerical model.

[Phys. Rev. Fluids 3, 044202] Published Mon Apr 30, 2018

Propulsion and maneuvering of an artificial microswimmer by two closely spaced waving elastic filaments

Mon, 04/30/2018 - 11:00

Author(s): Roei Elfasi, Yossef Elimelech, and Amir D. Gat

Hydrodynamic interaction between two adjacent waving elastic filaments is examined analytically and experimentally. Results show that antiphase beating is optimal for propulsion, hydrodynamic interaction modifies the optimal Sperm number, and phase difference between the filaments enables maneuvering.

[Phys. Rev. Fluids 3, 044203] Published Mon Apr 30, 2018

Finite volume solution for two-phase flow in a straight capillary

Fri, 04/27/2018 - 11:00

Author(s): Alexander Yelkhovsky and W. Val Pinczewski

Fluid inertia is usually ignored in network models used to predict flow in porous media. A model based on an averaged Navier-Stokes equation, validated for displacements in straight capillaries, is shown to capture the effects of inertia. Results suggest it can form the basis for more realistic network models.

[Phys. Rev. Fluids 3, 044003] Published Fri Apr 27, 2018

Self-sculpting of a dissolvable body due to gravitational convection

Thu, 04/26/2018 - 11:00

Author(s): Megan S. Davies Wykes, Jinzi Mac Huang, George A. Hajjar, and Leif Ristroph

Using candy “landforms” carved and reshaped by flowing water, laboratory experiments show how it is that some shapes keep a memory of earlier conditions as they develop while others forget the past, a fact that is important in geological dating and understanding how landscapes form.

[Phys. Rev. Fluids 3, 043801] Published Thu Apr 26, 2018

Higher-order force moments of active particles

Wed, 04/25/2018 - 11:00

Author(s): Babak Nasouri and Gwynn J. Elfring

The effects of higher-order force moments of active particles on the flow field induced by their motion are investigated. Using the reciprocal theorem, explicit expressions for the stresslet dipole, rotlet dipole, and potential dipole of an arbitrarily shaped active particle are provided.

[Phys. Rev. Fluids 3, 044101] Published Wed Apr 25, 2018

Direct numerical simulation of flow over dissimilar, randomly distributed roughness elements: A systematic study on the effect of surface morphology on turbulence

Wed, 04/25/2018 - 11:00

Author(s): Pourya Forooghi, Alexander Stroh, Philipp Schlatter, and Bettina Frohnapfel

Direct numerical simulations of flow over fourteen dense rough walls with varying geometry are conducted. The effect of a departure from same-size element roughness on turbulence statistics is studied, and the correlation of the roughness function with wall-normal fluctuations at the roughness crest is examined.

[Phys. Rev. Fluids 3, 044605] Published Wed Apr 25, 2018

Effects of nonuniform viscosity on ciliary locomotion

Tue, 04/24/2018 - 11:00

Author(s): Kourosh Shoele and Patrick S. Eastham

The swimming efficiency of an idealized microswimmer is theoretically examined where the pointwise viscosity depends weakly on the surrounding nutrient. Results show that optimal swimming efficiency is achieved differently in the constant- and variable-viscosity cases.

[Phys. Rev. Fluids 3, 043101] Published Tue Apr 24, 2018

Scalar flux modeling in turbulent flames using iterative deconvolution

Mon, 04/23/2018 - 11:00

Author(s): Z. M. Nikolaou, R. S. Cant, and L. Vervisch

A novel approach for modeling the scalar flux term in turbulent flames is presented. An iterative algorithm is used for “deblurring” the filtered field. Successive iterations lead to improved approximations of the original field, and explicit filtering is then used for modeling the scalar flux.

[Phys. Rev. Fluids 3, 043201] Published Mon Apr 23, 2018

Investigation of the Klinkenberg effect in a micro/nanoporous medium by direct simulation Monte Carlo method

Fri, 04/20/2018 - 11:00

Author(s): Guang Yang and Bernhard Weigand

We define effective pore size as a function of the porosity, the tortuosity, the contraction factor, and the intrinsic permeability of the porous medium. The Klinkenberg effect in different porous structures is found to be fully described by the Knudsen number characterized by this pore size.

[Phys. Rev. Fluids 3, 044201] Published Fri Apr 20, 2018

Thermal convection of liquid sodium in inclined cylinders

Fri, 04/20/2018 - 11:00

Author(s): Ruslan Khalilov, Ilya Kolesnichenko, Alexander Pavlinov, Andrey Mamykin, Alexander Shestakov, and Peter Frick

The effect of inclination on the sodium (Pr=0.0094) turbulent convection in a cylinder of unit aspect ratio was studied experimentally for a fixed Rayleigh number Ra=(1.47±0.03)×107, and the inclination angle varied from 0° (the Rayleigh-Benard convection) up to 90° with a step of 10°.

[Phys. Rev. Fluids 3, 043503] Published Fri Apr 20, 2018

Experimental and numerical investigation of electrohydrodynamic flow in a point-to-ring corona discharge

Fri, 04/20/2018 - 11:00

Author(s): Yifei Guan, Ravi Sankar Vaddi, Alberto Aliseda, and Igor Novosselov

An electrohydrodynamic flow in a point-to-ring corona configuration is investigated experimentally and numerically. A parameter X, defined as the ratio of the local electric force to the inertial term, characterizes the effect of electrohydrodynamic forcing on bulk flow.

[Phys. Rev. Fluids 3, 043701] Published Fri Apr 20, 2018

Minimal formulation of the linear spatial analysis of capillary jets: Validity of the two-mode approach

Wed, 04/18/2018 - 11:00

Author(s): H. González, P. A. Vazquez, F. J. García, and J. Guerrero

Linear models are often used for the evolution of capillary jets. Here we present the simplest linear spatial formulation and compare it to numerical simulations. Two magnitudes, shape deformation, and mean axial velocity, and two spatial modes are needed, with one of them decaying exponentially.

[Phys. Rev. Fluids 3, 044802] Published Wed Apr 18, 2018

Fingering patterns in magnetic fluids: Perturbative solutions and the stability of exact stationary shapes

Tue, 04/17/2018 - 11:00

Author(s): Pedro H. A. Anjos, Sérgio A. Lira, and José A. Miranda

Pattern formation processes in magnetic fluids confined in a Hele-Shaw cell and subjected to a radial magnetic field are studied. It is shown that the weakly nonlinear flow drives an initially circular interface towards nontrivial exact stationary shapes, which are dynamically stable.

[Phys. Rev. Fluids 3, 044002] Published Tue Apr 17, 2018

Numerical simulations of thermal convection on a hemisphere

Mon, 04/16/2018 - 11:00

Author(s): C.-H. Bruneau, P. Fischer, Y.-L. Xiong, and H. Kellay (Cyclobulle Collaboration)

Original numerical simulations of 2D turbulent convection on a hemisphere are presented. Nusselt and Reynolds numbers verify scaling laws consistent with Rayleigh-Bénard convection. Despite significant differences in geometry with classical 3D cells, the scaling laws of thermal convection are robust.

[Phys. Rev. Fluids 3, 043502] Published Mon Apr 16, 2018

Spheroidal and conical shapes of ferrofluid-filled capsules in magnetic fields

Mon, 04/16/2018 - 11:00

Author(s): Christian Wischnewski and Jan Kierfeld

The numerical and analytical investigation of elastic capsules filled with a ferrofluid/dielectric liquid in a uniform magnetic/electric field shows a discontinuous spherical-to-conical shape transition for increasing fields with diverging strains in the conical tips.

[Phys. Rev. Fluids 3, 043603] Published Mon Apr 16, 2018

Instability-driven frequency decoupling between structure dynamics and wake fluctuations

Fri, 04/13/2018 - 11:00

Author(s): Yaqing Jin, Jin-Tae Kim, and Leonardo P. Chamorro

The interaction between wall-mounted, flexible plates and wake fluctuations is experimentally investigated as a function of several geometrical and flow parameters. It is demonstrated that significant decoupling between the dynamics of the structures and flow may occur because of near-wake flow instability.

[Phys. Rev. Fluids 3, 044701] Published Fri Apr 13, 2018

Topology of two-dimensional turbulent flows of dust and gas

Thu, 04/12/2018 - 11:00

Author(s): Dhrubaditya Mitra and Prasad Perlekar

In a study of inertial particle velocity gradients and the corresponding flow topology, the density weighted joint distribution shows that converging saddle structures are most probable.

[Phys. Rev. Fluids 3, 044303] Published Thu Apr 12, 2018