Physical Review Fluids
Author(s): Kyle A. Pascioni and Louis N. Cattafesta
The slat flow field of a multi-element airfoil is experimentally studied. Mean turbulence statistics and phase-locked data link shear layer structures to narrowband peaks in the surface pressure spectra. Most notably, a bulk cove oscillation related to shear layer flapping is found.
[Phys. Rev. Fluids 3, 034607] Published Thu Mar 29, 2018
Dynamic domains of the Derviche Tourneur sodium experiment: Simulations of a spherical magnetized Couette flow
Author(s): E. J. Kaplan, H.-C. Nataf, and N. Schaeffer
A magnetized liquid sodium experiment and high-end numerical simulations are performed, both yielding similar magnetic signatures. Coherent flow structures are found to emerge from developed turbulence, some of which are related to linear instabilities of the mean flow.
[Phys. Rev. Fluids 3, 034608] Published Thu Mar 29, 2018
Author(s): Rodolfo Brandão, Eduardo O. Dias, and José A. Miranda
The immiscible three-dimensional (3D) radial viscous fingering problem in uniform porous media is studied. Linearly, algebraic growth of disturbances and the existence of regions of absolute stability are detected. On the nonlinear side, a basic mechanism leading to 3D tip-splitting is proposed.
[Phys. Rev. Fluids 3, 034002] Published Wed Mar 28, 2018
Author(s): Mingfei Zhao and Xin Yong
Transport and deposition of particles on the free surface of a drying droplet with a pinned contact line is studied by a multiphase lattice Boltzmann-Brownian dynamics method. The results reveal that both surface convection and interfacial confinement govern particle dynamics.
[Phys. Rev. Fluids 3, 034201] Published Wed Mar 28, 2018
Author(s): Martin Sauzade and Thomas Cubaud
The angular shape and dynamics of bubbles passing through a series of microfluidic extensions and contractions are investigated at large capillary numbers. The relationship between individual bubble deformation and collective distortion of segmented flows is examined in nonlinear microgeometries.
[Phys. Rev. Fluids 3, 034202] Published Wed Mar 28, 2018
Author(s): M. Vanierschot, M. Percin, and B. W. van Oudheusden
Double helical vortex breakdown is rarely observed in experiments and is mostly reported for laminar flows. A double helical breakdown structure in a turbulent annular jet is identified and its dynamics analyzed based on time-resolved tomographic particle image velocimetry measurements.
[Phys. Rev. Fluids 3, 034703] Published Wed Mar 28, 2018
Author(s): C. Chen, Z. Wang, and I. Gursul
An investigation of trailing vortices shed from an upstream wing interacting with a flexible downstream wing reveals the formation of a counterrotating vortex pair. The incident vortex is subject to increased meandering as it interacts with the wing.
[Phys. Rev. Fluids 3, 034704] Published Wed Mar 28, 2018
Author(s): Tao Wei and Fei Duan
The long-wave model accounting for gravity in evaporating layers shows that buoyancy has no influence on interfacial evolution, but it contributes to Marangoni-Rayleigh-Bénard convection in positive gravity and to Marangoni convection in negative gravity.
[Phys. Rev. Fluids 3, 034001] Published Tue Mar 27, 2018
Author(s): Zhong Zheng, Marco A. Fontelos, Sangwoo Shin, and Howard A. Stone
A similarity solution of the lubrication equations is presented for the leveling of an interface after a hole in it closes, in agreement with experimental observations.
[Phys. Rev. Fluids 3, 032001(R)] Published Mon Mar 26, 2018
Structural state diagram of concentrated suspensions of jammed soft particles in oscillatory shear flow
Author(s): Fardin Khabaz, Michel Cloitre, and Roger T. Bonnecaze
We use simulations of large amplitude oscillating shear flow of jamming concentrated suspensions of soft particles to study the developing internal structure, with transitions between glass to FCC and HCP crystals during the oscillation.
[Phys. Rev. Fluids 3, 033301] Published Mon Mar 26, 2018
Wakes behind surface-mounted obstacles: Impact of aspect ratio, incident angle, and surface roughness
Author(s): Nicolas Tobin and Leonardo P. Chamorro
The dependence of the wake strength behind a windbreak is experimentally investigated as a function of several relevant parameters. A semiempirical model for lateral wake deflection is formulated and found to compare well with experimental data.
[Phys. Rev. Fluids 3, 033801] Published Mon Mar 26, 2018
Author(s): L. Siconolfi, S. Camarri, and M. V. Salvetti
Flow patterns within a T-mixer are studied numerically when there is a temperature jump between the entering streams. The complex temperature distribution in the outlet channel affects the resulting mixing between the two miscible fluids as well as the bifurcation leading to the engulfment regime.
[Phys. Rev. Fluids 3, 033902] Published Mon Mar 26, 2018
Author(s): Cameron Stewart, S. Balachandar, and Thomas P. McGrath
Discrete element method simulations of a shockwave passing through a bed of particles show the formation of both macroscopic and microscopic particle structures. A particle-wave structure is initiated by a volume-fraction-dependent drag force and intensified by inelastic collisions.
[Phys. Rev. Fluids 3, 034308] Published Mon Mar 26, 2018
Author(s): Hyungwon John Park, Kevin O'Keefe, and David H. Richter
Rayleigh-Bénard convection is simulated to study the effects of inertial, nonisothermal particles on buoyancy-driven turbulent fluid. Distinct particle characteristics, such as gravitational settling and specific heat, are isolated to infer which are dominant in affecting the fluid.
[Phys. Rev. Fluids 3, 034307] Published Thu Mar 22, 2018
Author(s): Ralph J. Volino and Michael P. Schultz
A method for determining the wall shear stress under arbitrary streamwise pressure gradients and wall roughness conditions using Reynolds shear stress and mean velocity profile data is presented. Data from very near the wall are not required. The method is tested with experimental and direct numerical simulation data.
[Phys. Rev. Fluids 3, 034606] Published Thu Mar 22, 2018
Author(s): J. C. Serrano-García, S. Mendez-Díaz, and R. Zenit
The average properties of a bidisperse bubbly flow are studied experimentally. We find that the induced liquid velocity fluctuations are smaller than those expected from adding the monodisperse values for each size species, which indicates a strong dissipative interaction between species.
[Phys. Rev. Fluids 3, 034306] Published Wed Mar 21, 2018
Author(s): Michele Buzzicotti, Hussein Aluie, Luca Biferale, and Moritz Linkmann
The formation of intense quasi-2D cyclones characterizes the large-scale dynamics of any turbulent flow under strong rotation. A numerical study shows how 2D and 3D (homochiral) interactions cooperate for the inverse energy cascade.
[Phys. Rev. Fluids 3, 034802] Published Wed Mar 21, 2018
Author(s): Arnold J. T. M. Mathijssen, Raphaël Jeanneret, and Marco Polin
Cell interactions from predation to infection depend on direct contact and its duration. Experiments, simulations, and modeling show that for microswimmers contact is regulated by a competition between advection and diffusion akin to a generalized Taylor-dispersion phenomenon.
[Phys. Rev. Fluids 3, 033103] Published Tue Mar 20, 2018
Author(s): Zhuoyu Zhou and Rajat Mittal
The Aplysia, also known as ’sea hare’, is a marine mollusc that swims via large-amplitude flapping. With flow simulations we find a unique pattern in its wake of three vortex ring-like structures which overcome body drag. Swimming performance, however, appears to lag behind that of related species.
[Phys. Rev. Fluids 3, 033102] Published Fri Mar 16, 2018
Author(s): James T. Jenkins and Alexandre Valance
A two-phase continuum theory is derived for grains that collide with and jump above a bed of sand while accelerated by a turbulent wind. The resulting system of equations and boundary conditions for unsteady, uniform and steady, nonuniform flows is solved to determine saturation times and lengths.
[Phys. Rev. Fluids 3, 034305] Published Fri Mar 16, 2018