Latest papers in fluid mechanics
Numerical forcing scheme to generate passive scalar mixing on the centerline of turbulent round jets in a triply periodic box
Author(s): Kyupaeck Jeff Rah and Guillaume Blanquart
A forcing technique is devised to generate centerline scalar mixing of round jets in a triply periodic box. It is derived from the scalar transport equation using a Reynolds-like decomposition of the scalar field. The result is a combination of a mean gradient term and a linear scalar term.
[Phys. Rev. Fluids 4, 124504] Published Mon Dec 30, 2019
Solute transport in porous media studied by lattice Boltzmann simulations at pore scale and x-ray tomography experiments
Author(s): Chunwei Zhang, Tetsuya Suekane, Kosuke Minokawa, Yingxue Hu, and Anindityo Patmonoaji
With the aid of nondestructive microfocus x-ray computed tomography (CT), we performed three-dimensional (3D) tracer dispersion experiments on randomly unconsolidated packed beds. Plumes of nonreactive sodium iodide solution were point injected into a sodium chloride solvent as a tracer for the eval...
[Phys. Rev. E 100, 063110] Published Thu Dec 26, 2019
Author(s): Timothy J. O'Sullivan, Sridhar K. Kannam, Debadi Chakraborty, Billy D. Todd, and John E. Sader
Nonequilibrium and equilibrium classical molecular dynamics simulations of the linear viscoelastic response of water are performed. Comparison with available measurements are reported. Anomalous behavior for frequencies above 2 THz is observed, which is yet to be understood.
[Phys. Rev. Fluids 4, 123302] Published Thu Dec 26, 2019
Author(s): Charlie Lin and Vivek Narsimhan
A simulation of deflated vesicles in linear flows finds that their shape stability is unaffected by moderately rotational flows, where the results collapse to those of extensional flow by a simple scaling factor. Vesicles in near shear flows develop an asymmetrical shape that increases their critical capillary number.
[Phys. Rev. Fluids 4, 123606] Published Thu Dec 26, 2019
Author(s): P. Lin, X. Lin, L. E. Johns, and R. Narayanan
We show that the shape and stability of any static liquid bridge can be solved from a master problem obtained from a model of a pressure-controlled experiment.
[Phys. Rev. Fluids 4, 123904] Published Thu Dec 26, 2019
Author(s): Brandon M. Behring and Roy H. Goodman
We develop an alternate method for investigating the stability of a one-parameter family of periodic solutions of the four-vortex problem known as ‘leapfrogging’ orbits and confirm the value of a bifurcation parameter. This approach could be applied to other related and more general problems.
[Phys. Rev. Fluids 4, 124703] Published Thu Dec 26, 2019
Author(s): Zijing Ding and Elena Marensi
We investigate the upper bound on angular momentum transport in Taylor-Couette flow theoretically and numerically by a one-dimensional background field method. The flow is bounded between a rotating inner cylinder of radius Ri and a fixed outer cylinder of radius Ro. A variational problem is formula...
[Phys. Rev. E 100, 063109] Published Tue Dec 24, 2019
Author(s): Basile Radisson, Juliette Piketty-Moine, and Christophe Almarcha
The variation in the wrinkling of a flame burning down inside a vertical Hele-Shaw cell is related to flexure modes of the walls of the cell and a Faraday-like instability of the the flame front.
[Phys. Rev. Fluids 4, 121201(R)] Published Tue Dec 24, 2019
Author(s): John M. Kolinski, Ramin Kaviani, Dylan Hade, and Shmuel M. Rubinstein
Experiments show that prior to impact upon a solid surface, a droplet compresses the air beneath it into a nanometer-scale film. This air film is destroyed by the local initiation of liquid-solid contact, forming capillary bridges. A capillary wave leads the advancing wetting front, limiting its speed.
[Phys. Rev. Fluids 4, 123605] Published Tue Dec 24, 2019
Author(s): Akhil Varma and Sébastien Michelin
A theoretical framework based on the method of reflections for Laplace’s and Stokes’ equations is developed to systematically determine multibody chemohydrodynamic interactions of autophoretic colloids. This approach is an efficient alternative to full numerical simulations of suspension dynamics.
[Phys. Rev. Fluids 4, 124204] Published Tue Dec 24, 2019
Author(s): Jeffrey McClure, Colin Pavan, and Serhiy Yarusevych
A detailed analysis of cylinder wake dynamics is presented for characteristic instabilities spanning laminar-to-turbulent transition regimes. A new three-dimensional vortex tracking algorithm is introduced to elucidate the vorticity transport and relate it to structural loads.
[Phys. Rev. Fluids 4, 124702] Published Tue Dec 24, 2019
Acoustic radiation force acting on a heavy particle in a standing wave can be dominated by the acoustic microstreaming
Author(s): Thierry Baasch, Alen Pavlic, and Jürg Dual
We numerically investigate the contribution of the microstreaming to the acoustic radiation force acting on a small elastic spherical particle placed into an ultrasonic standing wave. When an acoustic wave scatters on a particle the acoustic radiation force and the microstreaming appear as nonlinear...
[Phys. Rev. E 100, 061102(R)] Published Mon Dec 23, 2019
Author(s): Manish Kumar, Derek M. Walkama, Jeffrey S. Guasto, and Arezoo M. Ardekani
The swimming sperm of many external fertilizing marine organisms face complex fluid flows during their search for egg cells. Aided by chemotaxis, relatively weak flows are known to enhance sperm-egg fertilization rates through hydrodynamic guidance. However, strong flows have the potential to mechan...
[Phys. Rev. E 100, 063107] Published Fri Dec 20, 2019
Author(s): Konstantin V. Koshel, Dmitry V. Stepanov, Eugene A. Ryzhov, Pavel Berloff, and V. I. Klyatskin
This work deals with buoyant tracers floating at the ocean surface, where the geostrophic velocity component is two dimensional and rotational (nondivergent) and the ageostrophic component can contain rotational and potential (divergent) contributions that are comparable in size. We consider a rando...
[Phys. Rev. E 100, 063108] Published Fri Dec 20, 2019
Author(s): Alexis Bougouin, Laurent Lacaze, and Thomas Bonometti
Using laboratory experiments, the collapse of a liquid-saturated granular column in air on a horizontal plane is analyzed in light of the “column” Bond number, the grain diameter to capillary length ratio, the initial aspect ratio, the Stokes number, and the initial volume fraction.
[Phys. Rev. Fluids 4, 124306] Published Fri Dec 20, 2019
Bifurcation phenomena on the inertial focusing of a neutrally buoyant spherical particle suspended in square duct flows
Author(s): Hiroshi Yamashita, Tomoaki Itano, and Masako Sugihara-Seki
Several patterns of inertial particle focusing over a square cross section are experimentally observed for suspension flows through a square duct. A numerical study describes transitions between the focusing patterns in terms of the bifurcation of particle equilibrium positions.
[Phys. Rev. Fluids 4, 124307] Published Fri Dec 20, 2019
Author(s): Matteo B. Bertagni, Massimo Marro, Pietro Salizzoni, and Carlo Camporeale
The transport equation for the statistical moments of a passive scalar dispersed in a turbulent flow is solved. The analytical solution for the passive scalar variance is shown to fit wind tunnel data from a neutral turbulent boundary layer.
[Phys. Rev. Fluids 4, 124701] Published Fri Dec 20, 2019
Author(s): Yaqing Jin, Shyuan Cheng, and Leonardo P. Chamorro
The flow and drag induced by active pitching of plates in the wake of a cylinder of diameter d were experimentally studied for various plate lengths L as well as pitching frequencies fp and amplitudes A0 at Reynolds number Re=1.6×104. Planar particle image velocimetry and a load cell were used to ch...
[Phys. Rev. E 100, 063106] Published Thu Dec 19, 2019
Convection driven by internal heat sources and sinks: Heat transport beyond the mixing-length or “ultimate” scaling regime
Author(s): Benjamin Miquel, Simon Lepot, Vincent Bouillaut, and Basile Gallet
An asymptotic solution for convective flows driven by internal heating and cooling is derived. The solution is stable and realized by 2D direct numerical simulations at very high Rayleigh numbers. Even more surprisingly, it corresponds to heat transport enhancement beyond the mixing-length scaling regime.
[Phys. Rev. Fluids 4, 121501(R)] Published Thu Dec 19, 2019
Author(s): Christian Pedersen, John F. Niven, Thomas Salez, Kari Dalnoki-Veress, and Andreas Carlson
The relaxation process of an elastic sheet supported by a thin viscous film is studied. Asymptotic leveling regimes are identified as a function of the supporting layer thickness when the dynamics is driven either by elastic bending or by thermal fluctuations.
[Phys. Rev. Fluids 4, 124003] Published Thu Dec 19, 2019