Latest papers in fluid mechanics
Dynamics of paramagnetic and ferromagnetic ellipsoidal particles in shear flow under a uniform magnetic field
Author(s): Christopher A. Sobecki, Jie Zhang, Yanzhi Zhang, and Cheng Wang
We theoretically and numerically study the effects of a uniform magnetic field on the dynamics of ellipsoidal ferromagnetic and paramagnetic particles in a simple shear flow at low Reynolds number. With numerical simulations we further illustrate their lateral migration in wall-bounded shear flows.
[Phys. Rev. Fluids 3, 084201] Published Tue Aug 14, 2018
Author(s): Rausan Jewel, Andreea Panaitescu, and Arshad Kudrolli
The drag experienced by a spherical intruder settling through a medium composed of transparent granular hydrogels and water is measured as a function of its speed and depth. Internal visualization of the medium shows its flow to be localized around the advancing intruder.
[Phys. Rev. Fluids 3, 084303] Published Tue Aug 14, 2018
Multiscale velocity correlations in turbulence and Burgers turbulence: Fusion rules, Markov processes in scale, and multifractal predictions
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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