Latest papers in fluid mechanics

Effect of synthetic jet modulation schemes on the reduction of a laminar separation bubble

Physical Review Fluids - Mon, 03/12/2018 - 10:00

Author(s): J. H. Seo, F. Cadieux, R. Mittal, E. Deem, and L. Cattafesta

The response of a laminar separation bubble to synthetic jet forcing with various modulation schemes is numerically investigated. The study suggests that the effectiveness of synthetic jet-based flow control could be improved by carefully designing the spectral content of the modulation scheme.

[Phys. Rev. Fluids 3, 033901] Published Mon Mar 12, 2018

Single-particle dispersion in stably stratified turbulence

Physical Review Fluids - Mon, 03/12/2018 - 10:00

Author(s): N. E. Sujovolsky, P. D. Mininni, and M. P. Rast

We develop a model for particle dispersion observed in stably stratified flows, such as in the ocean and the nocturnal atmosphere, where turbulence is very efficient at mixing and diffusing transported quantities. The model opens new efficient paths for statistical prediction of particle dispersion.

[Phys. Rev. Fluids 3, 034603] Published Mon Mar 12, 2018

Revised model for the radiation force exerted by standing surface acoustic waves on a rigid cylinder

Physical Review E - Fri, 03/09/2018 - 10:00

Author(s): Shen Liang and Wang Chaohui

In this paper, a model for the radiation force exerted by standing surface acoustic waves (SSAWs) on a rigid cylinder in inviscid fluids is extended to account for the dependence on the Rayleigh angle. The conventional model for the radiation force used in the SSAW-based applications is developed in...

[Phys. Rev. E 97, 033103] Published Fri Mar 09, 2018

Modeling the effects of small turbulent scales on the drag force for particles below and above the Kolmogorov scale

Physical Review Fluids - Fri, 03/09/2018 - 10:00

Author(s): Mikhael Gorokhovski and Rémi Zamansky

A stochastic model is proposed for the response of heavy particles to the small scales of high Reynolds number turbulent flow. Particles below and above the Kolmogorov scale are both considered. In the context of large eddy simulations, this model is assessed by comparison with statistics from direct numerical simulations and experiments.

[Phys. Rev. Fluids 3, 034602] Published Fri Mar 09, 2018

Wake of inertial waves of a horizontal cylinder in horizontal translation

Physical Review Fluids - Fri, 03/09/2018 - 10:00

Author(s): Nathanaël Machicoane, Vincent Labarre, Bruno Voisin, Frédéric Moisy, and Pierre-Philippe Cortet

The inertial wave wake of a horizontal cylinder translated horizontally in a fluid rotating about the vertical is analyzed. Results show that, owing to horizontal invariance, the slender-body approximation leads to a quantitative theoretical model of the experimental wake, even for a nonslender body.

[Phys. Rev. Fluids 3, 034801] Published Fri Mar 09, 2018

Universal stability curve for pattern formation in pulsed gas-solid fluidized beds of sandlike particles

Physical Review Fluids - Thu, 03/08/2018 - 10:00

Author(s): Lilian de Martín, Coen Ottevanger, J. Ruud van Ommen, and Marc-Olivier Coppens

Granular matter can form regular patterns under periodic excitations, such as ripples on a sandy beach. Pattern formation can also be used to structure the dynamics of a fluidized bed. New experiments show that the pattern stability curve is governed by universal scaling, underpinned by fluid-dynamical fundamentals.

[Phys. Rev. Fluids 3, 034303] Published Thu Mar 08, 2018

Time-dependent particle migration and margination in the pressure-driven channel flow of blood

Physical Review Fluids - Wed, 03/07/2018 - 10:00

Author(s): Qin M. Qi and Eric S. G. Shaqfeh

The time evolution of the red blood cell and platelet concentration distributions in pressure-driven flow through a straight channel is studied using a coarse-grained theory with comparison to boundary integral simulations. Key time scales and entrance lengths to reach steady state are reported.

[Phys. Rev. Fluids 3, 034302] Published Wed Mar 07, 2018

Three-dimensional simulations of void collapse in energetic materials

Physical Review Fluids - Tue, 03/06/2018 - 10:00

Author(s): Nirmal Kumar Rai and H. S. Udaykumar

We study the dynamics of void collapse and hot spot formation with 3D reactive void collapse simulations for various void shapes. We find that dimensionality plays an important role in hot-spot dynamics, underlining the importance of 3D simulations.

[Phys. Rev. Fluids 3, 033201] Published Tue Mar 06, 2018

Competition between drag and Coulomb interactions in turbulent particle-laden flows using a coupled-fluid–Ewald-summation based approach

Physical Review Fluids - Tue, 03/06/2018 - 10:00

Author(s): Yuan Yao and Jesse Capecelatro

A new method is presented for capturing charged inertial particles in turbulence. Numerical simulations show that even in dilute suspensions, particles can self-induce an electric field because of preferential concentration by the particles, resulting in particle agglomeration and enhanced clustering.

[Phys. Rev. Fluids 3, 034301] Published Tue Mar 06, 2018

Contribution of large scale coherence to wind turbine power: A large eddy simulation study in periodic wind farms

Physical Review Fluids - Mon, 03/05/2018 - 10:00

Author(s): Tanmoy Chatterjee and Yulia T. Peet

We study massive wind farms with large eddy simultations to improve understanding of wind turbine interaction with atmospheric turbulence. Large scale structures are found to be linked to downdraft mechanisms contributing to turbine power and to modulation of near wall eddies.

[Phys. Rev. Fluids 3, 034601] Published Mon Mar 05, 2018

Heavy inertial particles in turbulent flows gain energy slowly but lose it rapidly

Physical Review E - Fri, 03/02/2018 - 10:00

Author(s): Akshay Bhatnagar, Anupam Gupta, Dhrubaditya Mitra, and Rahul Pandit

We present an extensive numerical study of the time irreversibility of the dynamics of heavy inertial particles in three-dimensional, statistically homogeneous, and isotropic turbulent flows. We show that the probability density function (PDF) of the increment, W(τ), of a particle's energy over a ti...

[Phys. Rev. E 97, 033102] Published Fri Mar 02, 2018

Statistical symmetry restoration in fully developed turbulence: Renormalization group analysis of two models

Physical Review E - Thu, 03/01/2018 - 10:00

Author(s): N. V. Antonov, N. M. Gulitskiy, M. M. Kostenko, and A. V. Malyshev

In this paper we consider the model of incompressible fluid described by the stochastic Navier-Stokes equation with finite correlation time of a random force. Inertial-range asymptotic behavior of fully developed turbulence is studied by means of the field theoretic renormalization group within the ...

[Phys. Rev. E 97, 033101] Published Thu Mar 01, 2018

Role of flexural stiffness of leukocyte microvilli in adhesion dynamics

Physical Review Fluids - Thu, 03/01/2018 - 10:00

Author(s): Tai-Hsien Wu and Dewei Qi

Simulations using the Lattice-Boltzmann lattice-spring method (LLM) combined with adhesive dynamics (AD) find that the flexural stiffness of microvilli and their bending deformation have a significant effect on the rolling velocity and on the adhesive forces.

[Phys. Rev. Fluids 3, 031101(R)] Published Thu Mar 01, 2018

Viscoplastic squeeze flow between two identical infinite circular cylinders

Physical Review Fluids - Wed, 02/28/2018 - 10:00

Author(s): A. R. Koblitz, S. Lovett, and N. Nikiforakis

The interstitial squeeze flow between two approaching circular cylinders in a viscoplastic medium is studied numerically and semi-analytically. Yield stress effects external to the gap—not picked up by viscoplastic lubrication theory—are found to significantly affect the lubrication pressure.

[Phys. Rev. Fluids 3, 023301] Published Wed Feb 28, 2018

Flow through triple helical microchannel

Physical Review Fluids - Wed, 02/28/2018 - 10:00

Author(s): Pravat Rajbanshi and Animangsu Ghatak

Flow analysis in triple-helical micro-channels via µ-PIV experiments and 3D simulations show generation of strong secondary flow at the channel cross-section. Such flow is expected to significantly enhance mixing between liquids in the laminar regime useful for a host of microfluidic applications.

[Phys. Rev. Fluids 3, 024201] Published Wed Feb 28, 2018

Time-dependent patterns in quasivertical cylindrical binary convection

Physical Review E - Mon, 02/26/2018 - 10:00

Author(s): Arantxa Alonso, Isabel Mercader, and Oriol Batiste

This paper reports on numerical investigations of the effect of a slight inclination α on pattern formation in a shallow vertical cylindrical cell heated from below for binary mixtures with a positive value of the Soret coefficient. By using direct numerical simulation of the three-dimensional Bouss...

[Phys. Rev. E 97, 023108] Published Mon Feb 26, 2018

Extremely rare collapse and build-up of turbulence in stochastic models of transitional wall flows

Physical Review E - Mon, 02/26/2018 - 10:00

Author(s): Joran Rolland

This paper presents a numerical and theoretical study of multistability in two stochastic models of transitional wall flows. An algorithm dedicated to the computation of rare events is adapted on these two stochastic models. The main focus is placed on a stochastic partial differential equation mode...

[Phys. Rev. E 97, 023109] Published Mon Feb 26, 2018

Symmetric wetting heterogeneity suppresses fluid displacement hysteresis in granular piles

Physical Review Fluids - Mon, 02/26/2018 - 10:00

Author(s): R. Moosavi, M. Schröter, and S. Herminghaus

Fluid displacement in random piles of spheres occurs with strong hysteresis. Increasing heterogeneity (spheres with different wettability) is expected to increase hysteresis. Instead, we show that under certain conditions, hysteresis can be almost completely suppressed by adding heterogeneity.

[Phys. Rev. Fluids 3, 024304] Published Mon Feb 26, 2018

Gyrotactic suppression and emergence of chaotic trajectories of swimming particles in three-dimensional flows

Physical Review Fluids - Fri, 02/23/2018 - 10:00

Author(s): S. I. Heath Richardson, A. W. Baggaley, and N. A. Hill

Pattern formation is an intriguing, and biologically important, feature of many motile microorganisms. A new study shows that gyrotatic swimmers can form complex patterns even in the presence of a chaotic background flow, through the local suppression of Lagrangian chaos.

[Phys. Rev. Fluids 3, 023102] Published Fri Feb 23, 2018

Particle-bearing currents in uniform density and two-layer fluids

Physical Review Fluids - Fri, 02/23/2018 - 10:00

Author(s): Bruce R. Sutherland, Murray K. Gingras, Calla Knudson, Luke Steverango, and Christopher Surma

Experiments of hypopycnal and mesopycnal currents demonstrate that the microscopic transport of fresh water in viscous boundary layers surrounding the settling particles significantly impacts the macroscopic current evolution.

[Phys. Rev. Fluids 3, 023801] Published Fri Feb 23, 2018


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