Physical Review Fluids
Author(s): Alice Nasto, P.-T. Brun, and A. E. Hosoi
Inspired by nectar-drinking bats, an experimental and theoretical study investigates viscous entrainment in hairy textures. The trapped liquid is modeled using a Darcy-Brinkmann-like approach and the drainage flow solution is derived. The results reveal an optimal hair density to maximize fluid uptake.
[Phys. Rev. Fluids 3, 024002] Published Wed Feb 07, 2018
Author(s): Sabrina Meninno, Aronne Armanini, and Michele Larcher
Vertical and transversal structures clearly change as interparticle interactions become more collisional. Bottom and lateral confinement prove to be decisive for friction and energy dissipation as experimental evidence shows.
[Phys. Rev. Fluids 3, 024301] Published Mon Feb 05, 2018
Author(s): Muhammad Rizwanur Rahman and Prashant R. Waghmare
When droplets roll down inclines, their velocities are affected by their characteristic size. Larger droplets will travel faster unless they’re too big. Droplets larger than a “critical” size travel more slowly. An investigation shows that this critical size is determined by the viscosity of the surrounding medium.
[Phys. Rev. Fluids 3, 023601] Published Fri Feb 02, 2018
Experimental study of the flow in the wake of a stationary sphere immersed in a turbulent boundary layer
Author(s): René van Hout, Jerke Eisma, Gerrit E. Elsinga, and Jerry Westerweel
3D flow measurements in the wake of a sphere positioned close to the wall in a turbulent boundary layer indicate that the wake deflects away from the wall as a result of induced motion of preferentially aligned, shed “hairpin” vortices. This is increasingly so with decreasing sphere-wall gap.
[Phys. Rev. Fluids 3, 024601] Published Fri Feb 02, 2018
Publisher's Note: Turbulence intermittency in a multiple-time-scale Navier-Stokes-based reduced model [Phys. Rev. Fluids <b>2</b>, 072601(R) (2017)]
Author(s): Perry L. Johnson and Charles Meneveau
[Phys. Rev. Fluids 3, 029901] Published Fri Feb 02, 2018
Author(s): Hangjie Ji and Thomas P. Witelski
Volatile viscous fluids on partially-wetting solid substrates can exhibit interesting dynamics and interfacial instabilities. A study of vapor condensation and fluid evaporation in a one-sided lubrication model incorporating surface tension, intermolecular effects, and evaporative fluxes is presented.
[Phys. Rev. Fluids 3, 024001] Published Thu Feb 01, 2018
Author(s): John Kim and Gary Leal
[Phys. Rev. Fluids 3, 010003] Published Wed Jan 31, 2018
Author(s): S. Sid, V. E. Terrapon, and Y. Dubief
Direct numerical simulations of a FENE-P fluid in both two- and three-dimensional straight periodic channels find that elasto-inertial turbulence is fundementally two-dimensional. The spurious effect of artificial diffusion of the polymer is demonstrated.
[Phys. Rev. Fluids 3, 011301(R)] Published Wed Jan 31, 2018
Author(s): J. J. Tao, Bruno Eckhardt, and X. M. Xiong
Numerical simulations of plane-Poiseuille flow find a state of sparse but persistent oblique turbulent bands in a Reynolds number range between about 660 and 800, which is below the anticipated directed percolation transition.
[Phys. Rev. Fluids 3, 011902(R)] Published Wed Jan 31, 2018
Author(s): Juncal Arbelaiz, Anand U. Oza, and John W. M. Bush
An integrated experimental and theoretical investigation of the promenade mode, a bound state formed by a pair of droplets walking side by side on the surface of a vibrating fluid bath, highlights the role of bouncing phase adaptation in stabilizing the promenade mode.
[Phys. Rev. Fluids 3, 013604] Published Wed Jan 31, 2018
Author(s): I. Paul, G. Papadakis, and J. C. Vassilicos
Passive scalar fine-scale structure is studied numerically for heated grid-element scalar turbulence. Scalar variance decays earlier in space than turbulent kinetic energy (both with dissipation). A −5/3 slope in the scalar-variance spectrum is found beyond the Kolmogorov-Obukhov-Corrsin theory.
[Phys. Rev. Fluids 3, 014612] Published Wed Jan 31, 2018
Publisher's Note: Deflection and trapping of a counter-rotating vortex pair by a flat plate [Phys. Rev. Fluids <b>2</b>, 124702 (2017)]
Author(s): Monika Nitsche
[Phys. Rev. Fluids 3, 019902] Published Wed Jan 31, 2018
Author(s): T. Van Buren, D. Floryan, N. Wei, and A. J. Smits
Experiments show that swimming speed has little impact on the forces or wake produced by a fishlike propulsor. Both continuous and intermittent swimming styles are explored. The results indicate that there may be no need to mimic a free-swimming (self-propelled) condition in laboratory studies.
[Phys. Rev. Fluids 3, 013103] Published Tue Jan 30, 2018
Author(s): F. Lachaussée, Y. Bertho, C. Morize, A. Sauret, and P. Gondret
Two different patterns of erosion are observed in steady flow past a vertical cylinder emerging from a granular bed: a large hole at the base of the cylinder or two side-by-side elongated holes in the wake of the cylinder.
[Phys. Rev. Fluids 3, 012302(R)] Published Mon Jan 29, 2018
Author(s): Yoshinobu Yamamoto and Yoshiyuki Tsuji
Direct numerical simulations of turbulent channel flows up to Reτ=8000 find logarithmic variations both in the mean velocity and streamwise turbulent variance, although these logarithmic regions do not agree with each other.
[Phys. Rev. Fluids 3, 012602(R)] Published Mon Jan 29, 2018
Author(s): Ritwik Ghoshal and Nilanjan Mitra
Domains of regular and irregular reflection for underwater oblique shock waves have been identified theoretically. We compare the Tait and Mie-Grüneisen equations of state in their ability to demonstrate physics of shock wave reflection and find implications for designing blast mitigation devices.
[Phys. Rev. Fluids 3, 013403] Published Mon Jan 29, 2018
Author(s): Stuart I. Benton and Miguel R. Visbal
Very-low-amplitude, high-frequency forcing is used to manipulate the laminar separation bubble on a NACA 0012 airfoil pitching at a constant rate. Properly tuning the forcing frequency to track the changing Kelvin-Helmholtz instability results in significant delay of the onset of dynamic stall.
[Phys. Rev. Fluids 3, 013907] Published Mon Jan 29, 2018
Author(s): Ali Mozaffari, Nima Sharifi-Mood, Joel Koplik, and Charles Maldarelli
The stability of the boundary-guided motion of a diffusiophoretically self-propelled locomotor along a planar wall to mechanical disturbances and Brownian forces is examined theoretically. The main goal is to understand the conditions under which this passively guided motion is stable.
[Phys. Rev. Fluids 3, 014104] Published Mon Jan 29, 2018
Author(s): Pascal S. Raux and Anne-Laure Biance
The cohesion of a wet grain assembly is encountered in many situations, such as in the fabrication of sandcastles, the preparation of couscous, crumbles, or other granulated systems. Two simple experiments on model liquid/bead mixtures are performed to understand the behavior of such systems.
[Phys. Rev. Fluids 3, 014301] Published Mon Jan 29, 2018
Author(s): Matthew Rockwood, Yangzi Huang, and Melissa Green
Coherent vortex structures are tracked in simulations of massively-separated and turbulent flows using Lagrangian saddles found as intersections of positive and negative finite-time Lyapunov exponent ridges. This allows vortices to be tracked objectively in time and space in a variety of flows.
[Phys. Rev. Fluids 3, 014702] Published Mon Jan 29, 2018