Latest papers in fluid mechanics

Multiscale velocity correlations in turbulence and Burgers turbulence: Fusion rules, Markov processes in scale, and multifractal predictions

Physical Review E - Mon, 08/13/2018 - 11:00

Author(s): Jan Friedrich, Georgios Margazoglou, Luca Biferale, and Rainer Grauer

We compare different approaches towards an effective description of multiscale velocity field correlations in turbulence. Predictions made by the operator-product expansion, the so-called fusion rules, are placed in juxtaposition to an approach that interprets the turbulent energy cascade in terms o...


[Phys. Rev. E 98, 023104] Published Mon Aug 13, 2018

Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow

Physical Review E - Mon, 08/13/2018 - 11:00

Author(s): Balachandra Suri, Jeffrey Tithof, Roman O. Grigoriev, and Michael F. Schatz

Recent studies suggest that unstable, nonchaotic solutions of the Navier-Stokes equation may provide deep insights into fluid turbulence. In this article, we present a combined experimental and numerical study exploring the dynamical role of unstable equilibrium solutions and their invariant manifol...


[Phys. Rev. E 98, 023105] Published Mon Aug 13, 2018

Effect of soluble surfactants on the stability of stratified flows through soft-gel-coated walls

Physical Review E - Mon, 08/13/2018 - 11:00

Author(s): B. Dinesh and S. Pushpavanam

The effect of a soluble surfactant on the linear stability of layered two-phase Poiseuille flows through soft-gel-coated parallel walls is studied in this paper. The focus is on determining the effect of the elastohydrodynamic coupling between the fluids and the soft-gel layers on the various flow i...


[Phys. Rev. E 98, 023106] Published Mon Aug 13, 2018

Bubble collapse and jet formation in corner geometries

Physical Review Fluids - Mon, 08/13/2018 - 11:00

Author(s): Yoshiyuki Tagawa and Ivo R. Peters

The collapse of a vapor bubble in a corner generates a jet whose direction depends on the corner opening angle and bubble position. Experimental data is found to agree well with a potential flow model that gives analytical solutions for a family of corner opening angles.


[Phys. Rev. Fluids 3, 081601(R)] Published Mon Aug 13, 2018

Probing the strain-rotation balance in non-Newtonian turbulence with inertial particles

Physical Review Fluids - Thu, 08/09/2018 - 11:00

Author(s): Michael Sinhuber, Joseph G. Ballouz, and Nicholas T. Ouellette

Experimental observations of the pair correlation function of small inertial particles in a turbulent flow of dilute polymer solutions shows that particle clustering increases with the concentration of polymers, possibly reflecting a reduction of vorticity relative to straining.


[Phys. Rev. Fluids 3, 082602(R)] Published Thu Aug 09, 2018

Energy spectrum in the dissipation range

Physical Review Fluids - Wed, 08/08/2018 - 11:00

Author(s): Sualeh Khurshid, Diego A. Donzis, and K. R. Sreenivasan

Numerical simulations of isotropic turbulence find that the energy spectrum in the dissipation range cannot be described by a single exponential for Rλ>20, and that this effect is associated with intermittent energy transfer.


[Phys. Rev. Fluids 3, 082601(R)] Published Wed Aug 08, 2018

Pore-scale modeling of phase change in porous media

Physical Review Fluids - Wed, 08/08/2018 - 11:00

Author(s): Luis Cueto-Felgueroso, Xiaojing Fu, and Ruben Juanes

Liquid-vapor phase change is simulated in a porous medium, using a diffuse-interface model and the van der Waals equation of state. The role of wettability and pore space geometry on phase separation and on the propagation of evaporation fronts is investigated.


[Phys. Rev. Fluids 3, 084302] Published Wed Aug 08, 2018

Edge effect: Liquid sheet and droplets formed by drop impact close to an edge

Physical Review Fluids - Tue, 08/07/2018 - 11:00

Author(s): S. Lejeune, T. Gilet, and L. Bourouiba

Liquid sheet fragmentation is ubiquitous in nature and may shape phenomena such as the rain-induced propagation of foliar diseases. An experimental study investigates the formation and fragmentation of an asymmetric liquid sheet upon impact of a drop close to the edge of a solid substrate.


[Phys. Rev. Fluids 3, 083601] Published Tue Aug 07, 2018

Evolution of anisotropy in direct numerical simulations of MHD turbulence in a strong magnetic field on elongated periodic domains

Physical Review Fluids - Tue, 08/07/2018 - 11:00

Author(s): X. M. Zhai and P. K. Yeung

Time development (from top to bottom) of vortical structures (in red) in background of low vorticity (blue) in planar cross-sections of turbulence subjected to magnetic field on an elongated domain of aspect ratio 8, at 16384×20482 grid resolution.


[Phys. Rev. Fluids 3, 084602] Published Tue Aug 07, 2018

Intense structures of different momentum fluxes in turbulent channels

Physical Review Fluids - Tue, 08/07/2018 - 11:00

Author(s): Kosuke Osawa and Javier Jiménez

The effects of the ambiguity in the definition of the Reynolds stresses to the coherent structures in wall turbulence are studied. It is confirmed that sweeps, ejections, and rollers are robust features of the flow.


[Phys. Rev. Fluids 3, 084603] Published Tue Aug 07, 2018

Oscillatory instability in a reaction front separating fluids of different densities

Physical Review E - Mon, 08/06/2018 - 11:00

Author(s): Dan Coroian and Desiderio A. Vasquez

Reaction fronts described by the Kuramoto-Sivashinsky (KS) equation can exhibit complex behavior as they separate reacted from unreacted fluids. If the fluid of higher density is above a fluid of lower density, then the Rayleigh-Taylor instability can lead to fluid motion. In the reverse situation, ...


[Phys. Rev. E 98, 023102] Published Mon Aug 06, 2018

Ion partitioning effect on the electrophoresis of a soft particle with hydrophobic core

Physical Review E - Mon, 08/06/2018 - 11:00

Author(s): Saurabh K. Maurya, Partha P. Gopmandal, S. Bhattacharyya, and H. Ohshima

A theoretical study on the electrophoresis of a soft particle made up of a charged hydrophobic inner core surrounded by polyelectrolyte layer (PEL) is made. The dielectric permittivity of the PEL and aqueous solution are considered to be different, which creates the ion partitioning effect. The ion ...


[Phys. Rev. E 98, 023103] Published Mon Aug 06, 2018

Rivulet flow of generalized Newtonian fluids

Physical Review Fluids - Mon, 08/06/2018 - 11:00

Author(s): F. H. H. Al Mukahal, B. R. Duffy, and S. K. Wilson

The general parametric solution for the steady unidirectional flow of a thin rivulet of a generalized Newtonian fluid is obtained and illustrated for Carreau and Ellis fluids. In particular, the solution is used to describe the behavior of a rivulet of a strongly shear-thinning Ellis fluid.


[Phys. Rev. Fluids 3, 083302] Published Mon Aug 06, 2018

Turbulent magnetohydrodynamic flow in a square duct: Comparison of zero and finite magnetic Reynolds number cases

Physical Review Fluids - Mon, 08/06/2018 - 11:00

Author(s): Vinodh Bandaru, Thomas Boeck, and Jörg Schumacher

The effect of finite magnetic Reynolds numbers (Rm∼102) on MHD flow in a square duct was studied using direct numerical simulations. The structure of the secondary mean flow is modified significantly and the streamwise anisotropy is strongly enhanced away from the boundary layers.


[Phys. Rev. Fluids 3, 083701] Published Mon Aug 06, 2018

Numerical study of the effects of chemical dispersant on oil transport from an idealized underwater blowout

Physical Review Fluids - Mon, 08/06/2018 - 11:00

Author(s): Bicheng Chen, Di Yang, Charles Meneveau, and Marcelo Chamecki

To investigate how chemical dispersant impacts the transport of oil slicks such as the one from the Deepwater Horizon, a multiscale large-eddy simulation approach is used to show that the breakup of the oil slick into small droplets changes the mean transport direction and horizontal spread of the oil plume.


[Phys. Rev. Fluids 3, 083801] Published Mon Aug 06, 2018

Smart inertial particles

Physical Review Fluids - Mon, 08/06/2018 - 11:00

Author(s): Simona Colabrese, Kristian Gustavsson, Antonio Celani, and Luca Biferale

A reinforcement learning algorithm is applied to find quasi-optimal policies for buoyancy control of inertial probes/particles in order to avoid trapping and to reach specific regions when navigating in complex two- and three-dimensional flows.


[Phys. Rev. Fluids 3, 084301] Published Mon Aug 06, 2018

Scale locality of the energy cascade using real space quantities

Physical Review Fluids - Mon, 08/06/2018 - 11:00

Author(s): N. A. K. Doan, N. Swaminathan, P. A. Davidson, and M. Tanahashi

Scale locality of the energy cascade is demonstrated using direct numerical simulations data of homogeneous isotropic turbulence with Taylor microscale Reynolds numbers ranging from 37 to 1131. The range of influential scales for this scale locality is found to be independent of Reynolds number.


[Phys. Rev. Fluids 3, 084601] Published Mon Aug 06, 2018

Inertial spheroids in homogeneous, isotropic turbulence

Physical Review E - Fri, 08/03/2018 - 11:00

Author(s): Amal Roy, Anupam Gupta, and Samriddhi Sankar Ray

We study the rotational dynamics of inertial disks and rods in three-dimensional, homogeneous, isotropic turbulence. In particular, we show how the alignment and the decorrelation timescales of such spheroids depend, critically, on both the level of inertia and the aspect ratio of these particles. T...


[Phys. Rev. E 98, 021101(R)] Published Fri Aug 03, 2018

Fluctuation analysis of the atmospheric energy cycle

Physical Review E - Fri, 08/03/2018 - 11:00

Author(s): Richard Blender, Denny Gohlke, and Frank Lunkeit

The atmosphere gains available potential energy by solar radiation and dissipates kinetic energy mainly in the atmospheric boundary layer. We analyze the fluctuations of the global mean energy cycle defined by Lorenz in a simulation with a simplified hydrostatic model. The energy current densities a...


[Phys. Rev. E 98, 023101] Published Fri Aug 03, 2018

Diffusion of self-propelled particles in complex media

Physical Review Fluids - Thu, 08/02/2018 - 11:00

Author(s): Juan L. Aragones, Shahrzad Yazdi, and Alfredo Alexander-Katz

An investigation of the behavior of self-propelled particles in complex media finds a transition from thermal diffusion to collision-driven diffusion as the particle area fraction is increased. Collisions with passive particles increases the rotational diffusion of the self-propelled particles, leading to their “self-trapping.”


[Phys. Rev. Fluids 3, 083301] Published Thu Aug 02, 2018

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