Latest papers in fluid mechanics

Nonlinear harmonic generation by internal waves in a density staircase

Physical Review Fluids - Tue, 11/20/2018 - 10:00

Author(s): Scott Wunsch

Climate change in the Arctic Ocean will subject its thermohaline staircases to increased internal wave activity. An exploration of the nonlinear conversion of incident waves to trapped staircase waves identifies wave number and frequency bands where energy transfer may be significant.

[Phys. Rev. Fluids 3, 114803] Published Tue Nov 20, 2018

Lagrangian acceleration in Rayleigh-Bénard convection at various aspect ratios

Physical Review Fluids - Mon, 11/19/2018 - 10:00

Author(s): Jin-Tae Kim, Shikun Shen, Steven L. DiMarco, Yaqing Jin, and Leonardo P. Chamorro

Lagrangian dynamics of turbulent Rayleigh-Bénard convection is studied experimentally with 3D particle tracking velocimetry at various aspect ratios G. Insight on the pair dispersion, conditional acceleration probability density functions, and roll dynamics induced by G was found from nearly 3.5×107 events.

[Phys. Rev. Fluids 3, 113502] Published Mon Nov 19, 2018

Front evaporation effects on wicking in two- and three-dimensional porous domains

Physical Review E - Fri, 11/16/2018 - 10:00

Author(s): Eric M. Benner and Dimiter N. Petsev

We present the equations for wicking in two- and three-dimensional porous media when liquid is evaporating through the wet front using the Green–Ampt saturated capillary flow model in polar and spherical geometries. The time-dependent behavior of two-dimensional wicking influenced by front interface...

[Phys. Rev. E 98, 053104] Published Fri Nov 16, 2018

Material transport in the left ventricle with aortic valve regurgitation

Physical Review Fluids - Fri, 11/16/2018 - 10:00

Author(s): Giuseppe Di Labbio, Jérôme Vétel, and Lyes Kadem

An investigation of a leaking aortic valve finds that it prompts double-jet filling in the compliant left ventricle of the heart, inducing complex and inefficient blood transport. This gives rise to increased blood residence time and the emergence of attracting material lines, presenting favorable conditions for thrombus formation.

[Phys. Rev. Fluids 3, 113101] Published Fri Nov 16, 2018

Characterization of superimposed instabilities in the planar extensional flow of viscoelastic fluids

Physical Review Fluids - Fri, 11/16/2018 - 10:00

Author(s): F. A. Cruz and M. A. Alves

Cross-slot devices are routinely used to study the extension of high molecular weight polymer molecules and DNA in solution. We simulate the extensional flow of Boger fluids in an optimised cross-slot rheometer and investigate various emerging time-dependent instabilities.

[Phys. Rev. Fluids 3, 113301] Published Fri Nov 16, 2018

Inertial range skewness of the longitudinal velocity derivative in locally isotropic turbulence

Physical Review Fluids - Fri, 11/16/2018 - 10:00

Author(s): S. Sukoriansky, E. Kit, E. Zemach, S. Midya, and H. J. S. Fernando

A velocity derivative skewness akin to inertial-scale motions of turbulence is introduced and studied analytically, numerically, and experimentally. As an alternative to a conventional fine-scale parameter, it has an advantage in measurability while retaining a connection to vorticity dynamics.

[Phys. Rev. Fluids 3, 114605] Published Fri Nov 16, 2018

Probing turbulent superstructures in Rayleigh-Bénard convection by Lagrangian trajectory clusters

Physical Review Fluids - Thu, 11/15/2018 - 10:00

Author(s): Christiane Schneide, Ambrish Pandey, Kathrin Padberg-Gehle, and Jörg Schumacher

Large-scale patterns in three-dimensional turbulent Rayleigh-Bénard convection in a large-aspect-ratio cell are probed by the clustering of Lagrangian particle trajectories.

[Phys. Rev. Fluids 3, 113501] Published Thu Nov 15, 2018

Particle-laden exchange flows in inclined pipes

Physical Review Fluids - Thu, 11/15/2018 - 10:00

Author(s): Nima Mirzaeian and Kamran Alba

Intrusion of a particle-laden mixture into a pure fluid is studied experimentally within a duct. Applications are found in the discharge of slurries, mine tailings, pastes, sludge, effluents, and sewage. Exotic sedimentary, transitionary, and mixing regimes are found over various inclination angles.

[Phys. Rev. Fluids 3, 114301] Published Thu Nov 15, 2018

Coexistence of solitons and extreme events in deep water surface waves

Physical Review Fluids - Tue, 11/13/2018 - 10:00

Author(s): A. Cazaubiel, G. Michel, S. Lepot, B. Semin, S. Aumaître, M. Berhanu, F. Bonnefoy, and E. Falcon

An experimental study reveals a new statistical regime for 1D propagation of deep-water gravity waves where coherent structures (solitons, extreme events) coexist with random waves. Such a state is predicted theoretically by integrable turbulence but thus far had not been observed in this context.

[Phys. Rev. Fluids 3, 114802] Published Tue Nov 13, 2018

Particle velocity distributions and velocity fluctuations of non-Brownian settling particles by particle-resolved direct numerical simulation

Physical Review E - Fri, 11/09/2018 - 10:00

Author(s): Ali Abbas Zaidi

Settling dynamics of non-Brownian particles is investigated using particle-resolved direct numerical simulations. There are two aims of this paper: first is to study the variation of particle velocity fluctuations with solid volume for a wide range of settling Reynolds number; second is to investiga...

[Phys. Rev. E 98, 053103] Published Fri Nov 09, 2018

Stability of the Blasius boundary layer over a heated plate in a temperature-dependent viscosity flow

Physical Review Fluids - Fri, 11/09/2018 - 10:00

Author(s): R. Miller, S. J. Garrett, P. T. Griffiths, and Z. Hussain

A stability analysis of the Blasius boundary layer formed by a fluid with a temperature-dependent viscosity is examined. The results inform whether hydrodynamically unstable flows may exist inside chemical vapor deposition reactors (CVD) and how a comprehensive CVD stability model can be developed.

[Phys. Rev. Fluids 3, 113902] Published Fri Nov 09, 2018

Experimental investigations of liquid falling films flowing under an inclined planar substrate

Physical Review Fluids - Fri, 11/09/2018 - 10:00

Author(s): Alexandros Charogiannis, Fabian Denner, Berend G. M. van Wachem, Serafim Kalliadasis, Benoit Scheid, and Christos N. Markides

Space/time-resolved film-thickness data are presented for liquid films flowing under an inverted planar substrate. Different flow regimes are observed depending on the inclination, liquid properties, and Reynolds number, with waves characterized by pronounced three-dimensionality and rivulet formation.

[Phys. Rev. Fluids 3, 114002] Published Fri Nov 09, 2018

Topographical effects of roughness on turbulence statistics in roughness sublayer

Physical Review Fluids - Fri, 11/09/2018 - 10:00

Author(s): J. Yuan and M. Aghaei Jouybari

Current understanding of turbulence in the vicinity of surface roughness is mostly limited to narrow-scale or regular roughness geometries. A numerical analysis shows how various scales of a multiscale, realistic roughness affect friction, momentum balance, and turbulence production in the roughness sublayer.

[Phys. Rev. Fluids 3, 114603] Published Fri Nov 09, 2018

Structure, dynamics, and reconnection of vortices in a nonlocal model of superfluids

Physical Review Fluids - Thu, 11/08/2018 - 10:00

Author(s): Jason Reneuve, Julien Salort, and Laurent Chevillard

A nonlocal version of the Gross-Pitaevskii equation is investigated. The role of rotons in vortex reconnection is probed through numerical simulations of both local (standard) and nonlocal models. Observed dynamics are compared with the predictions of the local induction approximation.

[Phys. Rev. Fluids 3, 114602] Published Thu Nov 08, 2018

Characteristics of turbulent boundary layer large scale motions using direct fluctuating wall shear stress measurements

Physical Review Fluids - Thu, 11/08/2018 - 10:00

Author(s): Rommel J. Pabon, Lawrence Ukeiley, Mark Sheplak, and Casey Barnard Keane

A microelectromechanical-systems-based floating element wall-shear-stress sensor (1×1 mm) is validated in a turbulent boundary layer for its ability to measure characteristics of large-scale motions.

[Phys. Rev. Fluids 3, 114604] Published Thu Nov 08, 2018

Control of flow around a low Reynolds number airfoil using longitudinal strips

Physical Review Fluids - Wed, 11/07/2018 - 10:00

Author(s): Seunghyun Cho, Jooha Kim, and Haecheon Choi

Longitudinal strips are suggested as a new device that can significantly increase the aerodynamic performance of a low Reynolds number airfoil at post-stall angles of attack. Its mechanism relies on the generation of corner vortices that delay flow separation on the airfoil suction surface.

[Phys. Rev. Fluids 3, 113901] Published Wed Nov 07, 2018

Axial and radial patterns of a bidispersed suspension in a fully filled horizontal rotating cylinder

Physical Review E - Tue, 11/06/2018 - 10:00

Author(s): John C. Nasaba and Anugrah Singh

We report on the pattern formation in a horizontal rotating cylinder fully filled with bidispersed suspension composed of non-Brownian settling and floating particles. The effect of particle mixing of different buoyancy and shape on the axial and radial pattern formation was investigated using flow ...

[Phys. Rev. E 98, 053102] Published Tue Nov 06, 2018

Lean premixed reacting flows with swirl and wall-separation zones in a contracting open circular chamber

Physical Review Fluids - Tue, 11/06/2018 - 10:00

Author(s): Zvi Rusak, Yuxin Zhang, Jung J. Choi, and Shixiao Wang

A model problem of low-Mach number lean premixed reacting swirling flows with wall-separation zones in a contracting open chamber is studied. A theoretical feasibility for a technology of swirl-assisted combustion where the reaction zone is supported by a wall-separation zone is established.

[Phys. Rev. Fluids 3, 113201] Published Tue Nov 06, 2018

Influence of interfacial elasticity on liquid entrainment in thin foam films

Physical Review Fluids - Tue, 11/06/2018 - 10:00

Author(s): Gigi Lin, John M. Frostad, and Gerald G. Fuller

Thin-film experiments with an interferometric apparatus show an absence of a strong relationship between interfacial elasticity and liquid entrainment in thin foam films, which can affect rational design of aesthetic and tactile properties in foaming consumer products.

[Phys. Rev. Fluids 3, 114001] Published Tue Nov 06, 2018

Temperature gradient induced double stabilization of the evaporation front within a drying porous medium

Physical Review Fluids - Tue, 11/06/2018 - 10:00

Author(s): N. Vorhauer, E. Tsotsas, and M. Prat

The flow of water vapor against temperature gradients naturally occurring in drying of porous media leads to condensation and simultaneous gas-liquid invasion of pore space. This phenomenon is studied with a model porous medium in a microfluidic device and a pore network model of drying and imbibition.

[Phys. Rev. Fluids 3, 114201] Published Tue Nov 06, 2018


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