Latest papers in fluid mechanics

Dissipation, intermittency, and singularities in incompressible turbulent flows

Physical Review E - Thu, 05/03/2018 - 11:00

Author(s): P. Debue, V. Shukla, D. Kuzzay, D. Faranda, E.-W. Saw, F. Daviaud, and B. Dubrulle

We examine the connection between the singularities or quasisingularities in the solutions of the incompressible Navier-Stokes equation (INSE) and the local energy transfer and dissipation, in order to explore in detail how the former contributes to the phenomenon of intermittency. We do so by analy...

[Phys. Rev. E 97, 053101] Published Thu May 03, 2018

Characteristics of sources and sinks of momentum in a turbulent boundary layer

Physical Review Fluids - Thu, 05/03/2018 - 11:00

Author(s): D. Fiscaletti and B. Ganapathisubramani

In turbulent boundary layers, the wall-normal gradient of the Reynolds shear stress identifies momentum sources and sinks. The spacetime evolution of these small-scale motions is experimentally investigated in a turbulent boundary layer with time-resolved particle image velocimetry.

[Phys. Rev. Fluids 3, 054601] Published Thu May 03, 2018

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

Physical Review Fluids - 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

Shock-wave structure based on the Navier-Stokes-Fourier equations

Physical Review E - Mon, 04/30/2018 - 11:00

Author(s): F. J. Uribe and R. M. Velasco

We use the Navier-Stokes-Fourier constitutive equations to study plane shock waves in dilute gases. It is shown that the experimental information on the normalized density profiles can be fit by using the so-called soft sphere model, in which the viscosity and thermal conductivity are proportional t...

[Phys. Rev. E 97, 043117] Published Mon Apr 30, 2018

Flow produced by a free-moving floating magnet driven electromagnetically

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

Physical Review Fluids - 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

One-dimensional reduction of viscous jets. I. Theory

Physical Review E - Tue, 04/24/2018 - 11:00

Author(s): Cyril Pitrou

We build a general formalism to describe thin viscous jets as one-dimensional objects with an internal structure. We present in full generality the steps needed to describe the viscous jets around their central line, and we argue that the Taylor expansion of all fields around that line is convenient...

[Phys. Rev. E 97, 043115] Published Tue Apr 24, 2018

One-dimensional reduction of viscous jets. II. Applications

Physical Review E - Tue, 04/24/2018 - 11:00

Author(s): Cyril Pitrou

In a companion paper [Phys. Rev. E 97, 043115 (2018)], a formalism allowing to describe viscous fibers as one-dimensional objects was developed. We apply it to the special case of a viscous fluid torus. This allows to highlight the differences with the basic viscous string model and with its viscous...

[Phys. Rev. E 97, 043116] Published Tue Apr 24, 2018

Effects of nonuniform viscosity on ciliary locomotion

Physical Review Fluids - 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

Electrohydrodynamic channeling effects in narrow fractures and pores

Physical Review E - Mon, 04/23/2018 - 11:00

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

In low-permeability rock, fluid and mineral transport occur in pores and fracture apertures at the scale of micrometers and below. At this scale, the presence of surface charge, and a resultant electrical double layer, may considerably alter transport properties. However, due to the inherent nonline...

[Phys. Rev. E 97, 043114] Published Mon Apr 23, 2018

Scalar flux modeling in turbulent flames using iterative deconvolution

Physical Review Fluids - 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

Physical Review Fluids - 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

Discontinuous contact line motion of evaporating particle-laden droplet on superhydrophobic surfaces

Physical Review E - Fri, 04/20/2018 - 11:00

Author(s): Yutaka Yamada and Akihiko Horibe

The three-phase contact line motion on a superhydrophobic surface through particle-laden sessile droplet evaporation was investigated. Sample surfaces with micro- and nanoscale structures were generated by various durations of chemical treatment and SiO2 spherical particles with different sizes were...

[Phys. Rev. E 97, 043113] Published Fri Apr 20, 2018

Thermal convection of liquid sodium in inclined cylinders

Physical Review Fluids - 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


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