Latest papers in fluid mechanics

Edge effects on the fluttering characteristics of freely falling planar particles

Physical Review Fluids - Tue, 06/05/2018 - 11:00

Author(s): Luis Blay Esteban, John Shrimpton, and Bharathram Ganapathisubramani

Trajectories of N-sided polygons falling in quiescent media are used to measure the edge effect on the descent. A new length scale is proposed to estimate the equivalent dimensionless numbers. This allows use of the original phase diagram for disks and reconciles the effects of particle shape.

[Phys. Rev. Fluids 3, 064302] Published Tue Jun 05, 2018

Experimental investigation of the Peregrine Breather of gravity waves on finite water depth

Physical Review Fluids - Mon, 06/04/2018 - 11:00

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

A series of laboratory experiments were performed to study the Peregrine Breather evolution in a wave flume of finite depth and deep water. The experimental results are compared with computations based on both the nonlinear Schrödinger equation and the Dysthe equation, both with a dissipation term.

[Phys. Rev. Fluids 3, 064801] Published Mon Jun 04, 2018

Contact line friction of electrowetting actuated viscous droplets

Physical Review E - Fri, 06/01/2018 - 11:00

Author(s): Quoc Vo and Tuan Tran

Droplets on a surface immersed in oil are made to spread and retract by switching on and off a potential difference between the droplets and the surface. The authors find that the contact line friction depends on the viscosities of the droplet and the surrounding oil and that it does not depend significantly on the driving force or the direction of motion.

[Phys. Rev. E 97, 063101] Published Fri Jun 01, 2018

Inhomogeneous growth of fluctuations of concentration of inertial particles in channel turbulence

Physical Review Fluids - Fri, 06/01/2018 - 11:00

Author(s): Itzhak Fouxon, Lukas Schmidt, Peter Ditlevsen, Maarten van Reeuwijk, and Markus Holzner

We investigate how an initially uniform distribution of small inertial particles evolves due to transport by turbulent channel flow. Concentration fluctuations grow as particles approach a multifractal attractor with strong dependence on the distance to the wall which can be faster than exponential.

[Phys. Rev. Fluids 3, 064301] Published Fri Jun 01, 2018

Permeability of solid foam: Effect of pore connections

Physical Review E - Thu, 05/31/2018 - 11:00

Author(s): V. Langlois, V. H. Trinh, C. Lusso, C. Perrot, X. Chateau, Y. Khidas, and O. Pitois

In this paper, we study how the permeability of solid foam is modified by the presence of membranes that close partially or totally the cell windows connecting neighboring pores. The finite element method (FEM) simulations computing the Stokes problem are performed at both pore and macroscopic scale...

[Phys. Rev. E 97, 053111] Published Thu May 31, 2018

Single-bubble and multibubble cavitation in water triggered by laser-driven focusing shock waves

Physical Review E - Thu, 05/31/2018 - 11:00

Author(s): D. Veysset, U. Gutiérrez-Hernández, L. Dresselhaus-Cooper, F. De Colle, S. Kooi, K. A. Nelson, P. A. Quinto-Su, and T. Pezeril

In this study a single laser pulse spatially shaped into a ring is focused into a thin water layer, creating an annular cavitation bubble and cylindrical shock waves: an outer shock that diverges away from the excitation laser ring and an inner shock that focuses towards the center. A few nanosecond...

[Phys. Rev. E 97, 053112] Published Thu May 31, 2018

Meshfree and efficient modeling of swimming cells

Physical Review Fluids - Thu, 05/31/2018 - 11:00

Author(s): Meurig T. Gallagher and David J. Smith

We develop a tool for simulating three-dimensional locomotion in Stokes flow with highly resolved flow and swimming trajectories for multiple swimmers in the presence of surfaces. Key features include modularity, scalability, ease of implementation, and no need for mesh generation.

[Phys. Rev. Fluids 3, 053101] Published Thu May 31, 2018

Complexity of the laminar-turbulent boundary in pipe flow

Physical Review Fluids - Wed, 05/30/2018 - 11:00

Author(s): Nazmi Burak Budanur and Björn Hof

Numerical experiments demonstrate that the laminar-turbulent boundary in pipe flow exhibits qualitatively different regions whose dynamics resemble that of the nearby unstable invariant solutions. In addition, various different state space paths to turbulence from this boundary are illustrated.

[Phys. Rev. Fluids 3, 054401] Published Wed May 30, 2018

Fractality and the law of the wall

Physical Review E - Tue, 05/29/2018 - 11:00

Author(s): Haosen H. A. Xu and X. I. A. Yang

Fluid motions in the inertial range of isotropic turbulence are fractal, with their space-filling capacity slightly below regular three-dimensional objects, which is a consequence of the energy cascade. Besides the energy cascade, the other often encountered cascading process is the momentum cascade...

[Phys. Rev. E 97, 053110] Published Tue May 29, 2018

Evolution of wave patterns and temperature field in shock-tube flow

Physical Review Fluids - Tue, 05/29/2018 - 11:00

Author(s): A. D. Kiverin and I. S. Yakovenko

The gas-dynamical mechanism of ignition kernels formation in shock tubes is formulated on the basis of numerical analysis of the flow pattern developed behind the shock wave propagating in the rectangular tube filled with a reactive gaseous mixture.

[Phys. Rev. Fluids 3, 053201] Published Tue May 29, 2018

Hexagonal convection patterns and their evolutionary scenarios in electroconvection induced by a strong unipolar injection

Physical Review Fluids - Tue, 05/29/2018 - 11:00

Author(s): Kang Luo, Jian Wu, Hong-Liang Yi, Lin-Hua Liu, and He-Ping Tan

Various flow patterns and their evolutionary scenarios in three-dimensional electroconvection are numerically investigated. Specifically, a careful comparison of the hexagonal pattern is made to the previous semianalytical stability analysis results.

[Phys. Rev. Fluids 3, 053702] Published Tue May 29, 2018

Instability waves and transition in adverse-pressure-gradient boundary layers

Physical Review Fluids - Tue, 05/29/2018 - 11:00

Author(s): Rikhi Bose, Tamer A. Zaki, and Paul A. Durbin

The role of instability waves (IW) in free-stream turbulence (FST) induced boundary-layer transition in an adverse pressure gradient is studied with direct simulations. IW are found relevant even at moderate FST intensity of 2%. The effect of FST spectrum and intensity on transition are explored.

[Phys. Rev. Fluids 3, 053904] Published Tue May 29, 2018

Combined effects of molecular geometry and nanoconfinement on liquid flows through carbon nanotubes

Physical Review E - Fri, 05/25/2018 - 11:00

Author(s): Kazuhiko Suga, Yuki Mori, Rintaro Moritani, and Masayuki Kaneda

Molecular dynamics simulations are carried out to investigate the geometry effects of diatomic molecules on liquid flows in carbon nanotubes (CNTs). Oxygen molecules are considered as the fluid inside armchair (n,n) (n=6–20) CNTs. The simulated fluid temperature and bulk pressure for the liquid stat...

[Phys. Rev. E 97, 053109] Published Fri May 25, 2018

Size distribution spectrum of noninertial particles in turbulence

Physical Review E - Thu, 05/24/2018 - 11:00

Author(s): Izumi Saito, Toshiyuki Gotoh, and Takeshi Watanabe

Collision-coalescence growth of noninertial particles in three-dimensional homogeneous isotropic turbulence is studied. Smoluchowski's coagulation equation describes the evolution of the size distribution of particles in this system. By applying a methodology based on turbulence theory, the equation...

[Phys. Rev. E 97, 053108] Published Thu May 24, 2018

Scalewise invariant analysis of the anisotropic Reynolds stress tensor for atmospheric surface layer and canopy sublayer turbulent flows

Physical Review Fluids - Thu, 05/24/2018 - 11:00

Author(s): Peter Brugger, Gabriel G. Katul, Frederik De Roo, Konstantin Kröniger, Eyal Rotenberg, Shani Rohatyn, and Matthias Mauder

The return-to-isotropy of turbulence across scales is studied for different thermal stratification and surface roughness regimes from measurements in the atmospheric boundary layer and it is compared with predictions of a homogenous model.

[Phys. Rev. Fluids 3, 054608] Published Thu May 24, 2018

Vortex line topology during vortex tube reconnection

Physical Review Fluids - Wed, 05/23/2018 - 11:00

Author(s): P. McGavin and D. I. Pontin

The evolving topology of vortex lines during reconnection of vortex tubes is addressed. New features of the reconnection process are revealed, such as the generation of many small flux rings, and of vorticity null points. Methods to measure changes in flux connectivity are discussed.

[Phys. Rev. Fluids 3, 054701] Published Wed May 23, 2018

Three-dimensional instabilities of natural convection between two differentially heated vertical plates: Linear and nonlinear complementary approaches

Physical Review E - Tue, 05/22/2018 - 11:00

Author(s): Zhenlan Gao, Berengere Podvin, Anne Sergent, Shihe Xin, and Jalel Chergui

The transition to the chaos of the air flow between two vertical plates maintained at different temperatures is studied in the Boussinesq approximation. After the first bifurcation at critical Rayleigh number Rac, the flow consists of two-dimensional (2D) corotating rolls. The stability of the 2D ro...

[Phys. Rev. E 97, 053107] Published Tue May 22, 2018

Thermally activated vapor bubble nucleation: The Landau-Lifshitz–Van der Waals approach

Physical Review Fluids - Tue, 05/22/2018 - 11:00

Author(s): Mirko Gallo, Francesco Magaletti, and Carlo Massimo Casciola

A continuum model embedding thermal fluctuations, capillarity, and hydrodynamic effects is proposed to investigate bubble cavitation. The simulations, validated against molecular dynamics, access multibubble nucleation statistics and long-time dynamics in unprecedentedly large domains.

[Phys. Rev. Fluids 3, 053604] Published Tue May 22, 2018

Wake meandering of a model wind turbine operating in two different regimes

Physical Review Fluids - Tue, 05/22/2018 - 11:00

Author(s): Daniel Foti, Xiaolei Yang, Filippo Campagnolo, David Maniaci, and Fotis Sotiropoulos

We present wind tunnel and numerical experiments of the flow behind a model wind turbine in optimal and sub-optimal regimes. Spatio-temporal filtering and dynamic mode decomposition reveal that the onset and amplitude of wake meandering are affected by both the operating regime and the nacelle.

[Phys. Rev. Fluids 3, 054607] Published Tue May 22, 2018

Basal melting driven by turbulent thermal convection

Physical Review Fluids - Mon, 05/21/2018 - 11:00

Author(s): Babak Rabbanipour Esfahani, Silvia C. Hirata, Stefano Berti, and Enrico Calzavarini

The evolution of heat flux through an initially solid pure substance that is heated from below and that undergoes both phase-change and natural convection is studied numerically and contrasted with the dynamics of the Rayleigh-Bénard system in laminar and turbulent regimes.

[Phys. Rev. Fluids 3, 053501] Published Mon May 21, 2018


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