Latest papers in fluid mechanics

Secondary flow in turbulent ducts with increasing aspect ratio

Physical Review Fluids - Thu, 05/17/2018 - 11:00

Author(s): R. Vinuesa, P. Schlatter, and H. M. Nagib

The secondary flow in wide turbulent ducts is characterized by means of high-order direct numerical simulations. New results indicate that ducts or experimental facilities with aspect ratios larger than 10 may, if properly designed, exhibit good agreement with results obtained from spanwise-periodic channel computations.

[Phys. Rev. Fluids 3, 054606] Published Thu May 17, 2018

Experimental measurement of interparticle acoustic radiation force in the Rayleigh limit

Physical Review E - Wed, 05/16/2018 - 11:00

Author(s): Abhishek Ray Mohapatra, Shahrokh Sepehrirahnama, and Kian-Meng Lim

Acoustophoresis is a form of contact-free particle manipulation in microfluidic devices. The precision of manipulation can be enhanced with better understanding of the acoustic radiation force. In this paper we present the measurements of interparticle radiation force between a pair of polystyrene b...

[Phys. Rev. E 97, 053105] Published Wed May 16, 2018

Variational method enabling simplified solutions to the linearized Boltzmann equation for oscillatory gas flows

Physical Review Fluids - Wed, 05/16/2018 - 11:00

Author(s): Daniel R. Ladiges and John E. Sader

Cercignani’s variational principle, originally derived for steady rarefied gas flows, is extended to unsteady flows exhibiting oscillatory time dependence. The utility of this theory is demonstrated by deriving approximate formulas and numerical results for Couette flow and Stokes’ second problem.

[Phys. Rev. Fluids 3, 053401] Published Wed May 16, 2018

Equatorially trapped convection in a rapidly rotating shallow shell

Physical Review Fluids - Wed, 05/16/2018 - 11:00

Author(s): Benjamin Miquel, Jin-Han Xie, Nicholas Featherstone, Keith Julien, and Edgar Knobloch

Motivated by the recent discovery of subsurface oceans on planetary moons, convective flows in shallow spherical shells set in rapid rotation are explored. A new equatorial beta-plane convection model that captures trapping of convection at low latitudes due to rotation is investigated.

[Phys. Rev. Fluids 3, 053801] Published Wed May 16, 2018

Non-normality and classification of amplification mechanisms in stability and resolvent analysis

Physical Review Fluids - Wed, 05/16/2018 - 11:00

Author(s): Sean Symon, Kevin Rosenberg, Scott T. M. Dawson, and Beverley J. McKeon

Eigenspectra and pseudospectra of the (turbulent) mean-linearized Navier-Stokes operator are used to characterize amplification mechanisms in laminar and turbulent flows in which linear mechanisms are important.

[Phys. Rev. Fluids 3, 053902] Published Wed May 16, 2018

Physics of singularities in pressure-impulse theory

Physical Review Fluids - Wed, 05/16/2018 - 11:00

Author(s): R. Krechetnikov

Classical pressure-impulse theory solution for water impact of a flat plate exhibits both singular initial fluid acceleration and a near-plate-edge singularity in the velocity field. Here the singularities are resolved by including effects of compressibility, viscosity, and surface tension.

[Phys. Rev. Fluids 3, 054003] Published Wed May 16, 2018

Rotations of large inertial cubes, cuboids, cones, and cylinders in turbulence

Physical Review Fluids - Wed, 05/16/2018 - 11:00

Author(s): Nimish Pujara, Theresa B. Oehmke, Ankur D. Bordoloi, and Evan A. Variano

Rotations of large, neutrally buoyant, anisotropic particles in isotropic turbulence are studied. The rotation rate probability density function and its moments are found to be simple functions of particle shape and size. These are compared with structure functions in the flow to understand the effects of finite particle size.

[Phys. Rev. Fluids 3, 054605] Published Wed May 16, 2018

Aerodynamic repellency of impacting liquids

Physical Review Fluids - Tue, 05/15/2018 - 11:00

Author(s): Anaïs Gauthier, Ambre Bouillant, Christophe Clanet, and David Quéré

Impacting drops can be reflected by moving solid plates, provided the surface moves fast enough. The threshold speed of bouncing is described and modeled, along with the dynamics of liquid removal. Viscous or low surface tension liquids, usually impossible to repel, are thus efficiently swept away.

[Phys. Rev. Fluids 3, 054002] Published Tue May 15, 2018

Self-similar gravity wave spectra resulting from the modulation of bound waves

Physical Review Fluids - Tue, 05/15/2018 - 11:00

Author(s): Guillaume Michel, Benoît Semin, Annette Cazaubiel, Florence Haudin, Thomas Humbert, Simon Lepot, Félicien Bonnefoy, Michaël Berhanu, and Éric Falcon

Experiments are performed in a large basin to investigate nonlinear gravity waves generated by a periodic or a slowly modulated forcing. High-frequency self-similar spectra ascribed to bound waves are reported, which share similarities with the ones observed in previous experiments of wave turbulence.

[Phys. Rev. Fluids 3, 054801] Published Tue May 15, 2018

Attached flow structure and streamwise energy spectra in a turbulent boundary layer

Physical Review E - Mon, 05/14/2018 - 11:00

Author(s): S. Srinath, J. C. Vassilicos, C. Cuvier, J.-P. Laval, M. Stanislas, and J.-M. Foucaut

On the basis of (i) particle image velocimetry data of a turbulent boundary layer with large field of view and good spatial resolution and (ii) a mathematical relation between the energy spectrum and specifically modeled flow structures, we show that the scalings of the streamwise energy spectrum E1...

[Phys. Rev. E 97, 053103] Published Mon May 14, 2018

Validation of model predictions of pore-scale fluid distributions during two-phase flow

Physical Review E - Mon, 05/14/2018 - 11:00

Author(s): Tom Bultreys, Qingyang Lin, Ying Gao, Ali Q. Raeini, Ahmed AlRatrout, Branko Bijeljic, and Martin J. Blunt

Pore-scale two-phase flow modeling is an important technology to study a rock's relative permeability behavior. To investigate if these models are predictive, the calculated pore-scale fluid distributions which determine the relative permeability need to be validated. In this work, we introduce a me...

[Phys. Rev. E 97, 053104] Published Mon May 14, 2018

Dynamic heterogeneity and conditional statistics of non-Gaussian temperature fluctuations in turbulent thermal convection

Physical Review Fluids - Mon, 05/14/2018 - 11:00

Author(s): Xiaozhou He, Yin Wang, and Penger Tong

We present a theoretical model with no free parameters to describe a class of turbulent fluctuations with an exponential tail in the probability density function. For turbulent thermal convection the model (solid line) is compared with measured temperature distributions (symbols), and agrees well.

[Phys. Rev. Fluids 3, 052401(R)] Published Mon May 14, 2018

Effects of wind on the dynamics of the central jet during drop impact onto a deep-water surface

Physical Review Fluids - Mon, 05/14/2018 - 11:00

Author(s): Xinan Liu, An Wang, Shuang Wang, and Dejun Dai

The cavity and central jet produced by the impact of a water drop on a water surface in a wind field are experimentally studied. Results show that the dynamics of the central jet are controlled by two mechanisms: the oblique impact caused by the wind and the wind drag directly acting on the jet.

[Phys. Rev. Fluids 3, 053602] Published Mon May 14, 2018

Mean-field kinetic theory approach to evaporation of a binary liquid into vacuum

Physical Review Fluids - Mon, 05/14/2018 - 11:00

Author(s): A. Frezzotti, L. Gibelli, D. A. Lockerby, and J. E. Sprittles

Evaporation of a binary liquid into vacuum is studied through a mean-field kinetic theory approach. It is found that evaporated atoms are distributed according to anisotropic Maxwellians, and evaporation coefficients are only mildly dependent on the liquid-vapor interface composition and temperature.

[Phys. Rev. Fluids 3, 054001] Published Mon May 14, 2018

Propelled microprobes in turbulence

Physical Review Fluids - Fri, 05/11/2018 - 11:00

Author(s): E. Calzavarini, Y. X. Huang, F. G. Schmitt, and L. P. Wang

The statistical properties of the measurements performed by tiny self-propelled probes drifting in a turbulent flow are studied by means of a numerical model system. Their nontrivial combination of Lagrangian and Eulerian features are highlighted both in fluid velocity and scalar field time-series.

[Phys. Rev. Fluids 3, 054604] Published Fri May 11, 2018

Role of medium heterogeneity and viscosity contrast in miscible flow regimes and mixing zone growth: A computational pore-scale approach

Physical Review Fluids - Tue, 05/08/2018 - 11:00

Author(s): Saied Afshari, S. Hossein Hejazi, and Apostolos Kantzas

The mixing length growth in the miscible displacement through granular porous media is evaluated. Scaling laws are proposed to quantify the role of medium heterogeneity, viscosity contrast, and injection rate on the solution mixing.

[Phys. Rev. Fluids 3, 054501] Published Tue May 08, 2018

Experimental study on the evolution of Peregrine breather with uniform-depth adverse currents

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

Author(s): B. Liao, Y. Ma, X. Ma, and G. Dong

A series of laboratory experiments were performed to study the evolution of Peregrine breather (PB) in a wave flume in finite depth, and wave trains were initially generated in a region of quiescent water and then propagated into an adverse current region for which the current velocity strength grad...

[Phys. Rev. E 97, 053102] Published Mon May 07, 2018

Absolute/convective secondary instabilities and the role of confinement in free shear layers

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

Author(s): Cristóbal Arratia, Saviz Mowlavi, and François Gallaire

Mixing layers can grow in time or space by vortex pairings that succeed each other in a nearly self-similar way. We use a point vortex model to study how confinement eventually limits this growth process, leading us to propose a wavelength selection mechanism for free shear layers with counterflow.

[Phys. Rev. Fluids 3, 053901] Published Mon May 07, 2018

Study of subgrid-scale velocity models for reacting and nonreacting flows

Physical Review Fluids - Fri, 05/04/2018 - 11:00

Author(s): I. Langella, N. A. K. Doan, N. Swaminathan, and S. B. Pope

The accuracy of subgrid scale velocity kinetic energy models for reacting and nonreacting flows is studied using direct numerical simulation data. The analysis shows the dissipation of momentum, not taken into account in existing models, to be the key factor. A new model, localized diffusion-dissipation, is proposed on the basis of this result.

[Phys. Rev. Fluids 3, 054602] Published Fri May 04, 2018

Inviscid criterion for decomposing scales

Physical Review Fluids - Fri, 05/04/2018 - 11:00

Author(s): Dongxiao Zhao and Hussein Aluie

Length scale in a flow depends on the decryption key used to decipher length scales and the communications between them. Analysis shows that some of the decryption keys widely used can, in fact, obfuscate the physics, whereas one of them allows us to unravel the correct multiscale dynamics.

[Phys. Rev. Fluids 3, 054603] Published Fri May 04, 2018


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