Physical Review Fluids
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
Experimental and numerical investigation of electrohydrodynamic flow in a point-to-ring corona discharge
Author(s): Yifei Guan, Ravi Sankar Vaddi, Alberto Aliseda, and Igor Novosselov
An electrohydrodynamic flow in a point-to-ring corona configuration is investigated experimentally and numerically. A parameter X, defined as the ratio of the local electric force to the inertial term, characterizes the effect of electrohydrodynamic forcing on bulk flow.
[Phys. Rev. Fluids 3, 043701] Published Fri Apr 20, 2018
Minimal formulation of the linear spatial analysis of capillary jets: Validity of the two-mode approach
Author(s): H. González, P. A. Vazquez, F. J. García, and J. Guerrero
Linear models are often used for the evolution of capillary jets. Here we present the simplest linear spatial formulation and compare it to numerical simulations. Two magnitudes, shape deformation, and mean axial velocity, and two spatial modes are needed, with one of them decaying exponentially.
[Phys. Rev. Fluids 3, 044802] Published Wed Apr 18, 2018
Fingering patterns in magnetic fluids: Perturbative solutions and the stability of exact stationary shapes
Author(s): Pedro H. A. Anjos, Sérgio A. Lira, and José A. Miranda
Pattern formation processes in magnetic fluids confined in a Hele-Shaw cell and subjected to a radial magnetic field are studied. It is shown that the weakly nonlinear flow drives an initially circular interface towards nontrivial exact stationary shapes, which are dynamically stable.
[Phys. Rev. Fluids 3, 044002] Published Tue Apr 17, 2018
Author(s): C.-H. Bruneau, P. Fischer, Y.-L. Xiong, and H. Kellay (Cyclobulle Collaboration)
Original numerical simulations of 2D turbulent convection on a hemisphere are presented. Nusselt and Reynolds numbers verify scaling laws consistent with Rayleigh-Bénard convection. Despite significant differences in geometry with classical 3D cells, the scaling laws of thermal convection are robust.
[Phys. Rev. Fluids 3, 043502] Published Mon Apr 16, 2018
Author(s): Christian Wischnewski and Jan Kierfeld
The numerical and analytical investigation of elastic capsules filled with a ferrofluid/dielectric liquid in a uniform magnetic/electric field shows a discontinuous spherical-to-conical shape transition for increasing fields with diverging strains in the conical tips.
[Phys. Rev. Fluids 3, 043603] Published Mon Apr 16, 2018
Author(s): Yaqing Jin, Jin-Tae Kim, and Leonardo P. Chamorro
The interaction between wall-mounted, flexible plates and wake fluctuations is experimentally investigated as a function of several geometrical and flow parameters. It is demonstrated that significant decoupling between the dynamics of the structures and flow may occur because of near-wake flow instability.
[Phys. Rev. Fluids 3, 044701] Published Fri Apr 13, 2018
Author(s): Dhrubaditya Mitra and Prasad Perlekar
In a study of inertial particle velocity gradients and the corresponding flow topology, the density weighted joint distribution shows that converging saddle structures are most probable.
[Phys. Rev. Fluids 3, 044303] Published Thu Apr 12, 2018
Author(s): Mohammad Danish and Charles Meneveau
A detailed study on the scale dependence of various quantities of interest, such as the population fraction of different flow-topologies, is presented. While the quantities appear close to scale invariant in inertial range, a “bump” is observed at length scales between the inertial and viscous ranges.
[Phys. Rev. Fluids 3, 044604] Published Wed Apr 11, 2018
Simulations of sheared dense noncolloidal suspensions: Evaluation of the role of long-range hydrodynamics
Author(s): Stany Gallier, François Peters, and Laurent Lobry
We find that the consequence of switching off long-range hydrodynamic interactions in simulations of concentrated suspension is that they can be switched off if considering the viscosity, but not if considering the diffusivity or particle velocities.
[Phys. Rev. Fluids 3, 042301(R)] Published Mon Apr 09, 2018
Author(s): Yiran Zhang and Susan J. Muller
Flow transitions in the settling of a sphere in non-shear-banding wormlike micelle solutions are mapped. The onset of unsteady sedimentation correlates with an extensional Deborah number, while the velocity fluctuations are related to a shear Deborah number and an elastic Mach number.
[Phys. Rev. Fluids 3, 043301] Published Mon Apr 09, 2018
Author(s): H. Perrin, D. Belardinelli, M. Sbragaglia, and B. Andreotti
How does a liquid-vapor interface in contact with a plate in motion react to the presence of defects at smaller scales? The hydrodynamics of such a system is investigated theoretically, offering a tractable mathematical framework to explore contact line motion through a disordered energy landscape.
[Phys. Rev. Fluids 3, 044001] Published Mon Apr 09, 2018
Author(s): Sumit Kumar Birwa, G. Rajalakshmi, Rama Govindarajan, and Narayanan Menon
New experiments show that collisions between a sphere and a plane immersed in a viscous fluid involve direct mechanical contact, in contrast to expectations based on earlier theory. An electrical probe is used to monitor short-time mechanics of contact formation during the rebound of the sphere.
[Phys. Rev. Fluids 3, 044302] Published Mon Apr 09, 2018
Numerical study of turbulent channel flow perturbed by spanwise topographic heterogeneity: Amplitude and frequency modulation within low- and high-momentum pathways
Author(s): Ankit Awasthi and William Anderson
The feedback between topographically driven turbulent secondary flows and modulation of small-scale amplitude and frequency is explored. Results demonstrate that modulation remains but differs intrinsically because of background secondary flows within the domain.
[Phys. Rev. Fluids 3, 044602] Published Mon Apr 09, 2018
Impact of a small ellipticity on the sustainability condition of developed turbulence in a precessing spheroid
Author(s): Yasufumi Horimoto, Gabriel Simonet-Davin, Atsushi Katayama, and Susumu Goto
An experimental investigation shows that the small ellipticity of a precessing spheroidal cavity has a significant impact on the flow transition from solid-body rotational flow to developed turbulence of a confined fluid. In contrast, the developed turbulence in the spheroid is almost identical to that in the sphere.
[Phys. Rev. Fluids 3, 044603] Published Mon Apr 09, 2018
Author(s): Richard J. A. M. Stevens, Alexander Blass, Xiaojue Zhu, Roberto Verzicco, and Detlef Lohse
Direct numerical simulations of highly turbulent Rayleigh-Bénard convection up to Rayleigh numbers Ra = 109 in horizontally periodic domains with aspect ratios up to Γ = 128, find superstructures of very large-scale and long living coherent structures.
[Phys. Rev. Fluids 3, 041501(R)] Published Fri Apr 06, 2018
Role of Marangoni stress during breakup of surfactant-covered liquid threads: Reduced rates of thinning and microthread cascades
Author(s): Pritish M. Kamat, Brayden W. Wagoner, Sumeet S. Thete, and Osman A. Basaran
Simulations and experiments resolve a long-standing controversy that the gradient of surface tension—Marangoni stress—rather than surface tension lowering is responsible for decelerated thinning rates and microthread cascades during breakup of surfactant-covered threads.
[Phys. Rev. Fluids 3, 043602] Published Fri Apr 06, 2018
Author(s): Antoine Delon, Alain Cartellier, and Jean-Philippe Matas
We evidence two regimes for the flapping instability of a liquid jet atomized by a gas stream: a first one where it is synchronized with an upstream shear instability, and a second one where frequency is independent of gas flow, simply controlled by the ratio of liquid velocity to liquid jet radius.
[Phys. Rev. Fluids 3, 043901] Published Fri Apr 06, 2018
Author(s): Sudarshan Konidena, Jonghoon Lee, K. Anki Reddy, and Anugrah Singh
Buoyant particle suspension in a horizontal rotating cylinder is known to exhibit axially oscillating particle bands in the centrifugal force dominant phase. Numerical simulations using Stokeslets as the particles were performed to investigate the behavior.
[Phys. Rev. Fluids 3, 044301] Published Fri Apr 06, 2018
Author(s): Antoine Campagne, Roumaissa Hassaini, Ivan Redor, Joël Sommeria, Thomas Valran, Samuel Viboud, and Nicolas Mordant
Experiments are performed in the Coriolis facility to investigate gravity surface wave turbulence. Results indicate that dissipation is responsible for the quantitative discrepancy between experimental and field measurement of the wave energy spectrum, which is systematically steeper in the lab.
[Phys. Rev. Fluids 3, 044801] Published Fri Apr 06, 2018