Physical Review E
Going beyond an old shockwave conjecture for improving upon Navier-Stokes
Author(s): Brad Lee Holian, Michel Mareschal, and Ramon Ravelo
Nonequilibrium molecular dynamics (NEMD) computer simulations of steady shockwaves in dense fluids and rarefied gases produce detailed shockwave profiles of mechanical and thermal properties. The Boltzmann equation, under the assumption of local thermodynamic equilibrium (LTE), leads to the first-or…
[Phys. Rev. E 110, 015105] Published Wed Jul 24, 2024
Orientational order and topological defects in a dilute solutions of rodlike polymers at low Reynolds number
Author(s): L. Puggioni and S. Musacchio
The relationship between the polymer orientation and the chaotic flow, in a dilute solution of rigid rodlike polymers at low Reynolds number, is investigated by means of direct numerical simulations. It is found that the rods tend to align with the velocity field in order to minimize the friction wi…
[Phys. Rev. E 110, 015104] Published Wed Jul 17, 2024
Investigations on the shock wave induced by collapse of a toroidal bubble
Author(s): Cheng Liu, Xiaobin Yang, Jingqi Li, Yiding Hu, Min Zhao, and Changhong Hu
When bubbles collapse near a wall, they typically experience an asymmetric deformation. This collapse leads to the creation of a jet that strikes the bubble interface, causing the formation of a toroidal bubble and the subsequent release of a water-hammer shock. In this study, we present a systemati…
[Phys. Rev. E 110, 015103] Published Tue Jul 16, 2024
Mixing in two-dimensional shear flow with smooth fluctuations
Author(s): Nikolay A. Ivchenko, Vladimir V. Lebedev, and Sergey S. Vergeles
Chaotic variations in flow speed up mixing of scalar fields via intensified stirring. This paper addresses the statistical properties of a passive scalar field mixing in a regular shear flow with random fluctuations against its background. We consider two-dimensional flow with shear component domina…
[Phys. Rev. E 110, 015102] Published Mon Jul 15, 2024
Coherent structures formed by small particles in traveling-wave flows
Author(s): Shogo Sensui, Shin Noguchi, Keiichiro Kato, and Ichiro Ueno
We experimentally verify the “phase locking model,” which describes the formation of one-dimensional coherent structures by low-Stokes-number particles as proposed by Pushkin et al. [Phys. Rev. Lett. 106, 234501 (2011)] in thermocapillary liquid bridges: When the particles form the coherent structur…
[Phys. Rev. E 110, 015101] Published Mon Jul 08, 2024
Poles, shocks, and tygers: The time-reversible Burgers equation
Author(s): Arunava Das, Pinaki Dutta, and Vishwanath Shukla
We construct a formally time-reversible, one-dimensional forced Burgers equation by imposing a global constraint of energy conservation, wherein the constant viscosity is modified to a fluctuating state-dependent dissipation coefficient. The system exhibits dynamical properties which bear strong sim…
[Phys. Rev. E 109, 065108] Published Tue Jun 18, 2024
Dual residence time for droplets to coalesce with a liquid surface
Author(s): Ting-Heng Hsieh, Wei-Chi Li, and Tzay-Ming Hong
When droplets approach a liquid surface, they have a tendency to merge in order to minimize surface energy. However, under certain conditions, they can exhibit a phenomenon called coalescence delay, where they remain separate for tens of milliseconds. This duration is known as the residence time or …
[Phys. Rev. E 109, 065109] Published Tue Jun 18, 2024
Generalized scaling laws for the irrotational motions bordering a turbulent region
Author(s): Marco Zecchetto, Ricardo P. Xavier, Miguel A. C. Teixeira, and Carlos B. da Silva
In turbulent free shear flows such as jets and wakes, and also in turbulent boundary layers, the turbulent region is bounded by a region of irrotational flow where the magnitude of the potential velocity fluctuations can be very high. This is particularly true close to the turbulent-nonturbulent int…
[Phys. Rev. E 109, 065107] Published Mon Jun 17, 2024
Propulsion of a three-sphere microrobot in a porous medium
Author(s): Chih-Tang Liao, Andrew Lemus, Ali Gürbüz, Alan C. H. Tsang, On Shun Pak, and Abdallah Daddi-Moussa-Ider
Microorganisms and synthetic microswimmers often encounter complex environments consisting of networks of obstacles embedded into viscous fluids. Such settings include biological media, such as mucus with filamentous networks, as well as environmental scenarios, including wet soil and aquifers. A fu…
[Phys. Rev. E 109, 065106] Published Thu Jun 13, 2024
Molecular dynamics study of the sonic horizon of microscopic Laval nozzles
Author(s): Helmut Ortmayer and Robert E. Zillich
A Laval nozzle can accelerate expanding gas above supersonic velocities, while cooling the gas in the process. This work investigates this process for microscopic Laval nozzles by means of nonequilibrium molecular dynamics simulations of stationary flow, using grand-canonical Monte Carlo particle re…
[Phys. Rev. E 109, 065104] Published Tue Jun 11, 2024
Precipitation-induced filament pattern of injected fluid controlled by a structured cell
Author(s): Shunsuke Tanaka, Kojiro Otoguro, Miyuki Kunihiro, Hiroki Ishikawa, and Yutaka Sumino
Mixing of two fluids can lead to the formation of a precipitate. If one of the fluids is injected into a confined space filled with the other, then a created precipitate disrupts the flow locally and forms complex spatiotemporal patterns. The relevance of controlling these patterns has been highligh…
[Phys. Rev. E 109, 065105] Published Tue Jun 11, 2024
Insights on phase speed and the critical Reynolds number of falling films
Author(s): Arghya Samanta
We revisit the studies of gravity-driven viscous falling films with and without imposed shear stress to provide new perspectives on phase speed and the critical Reynolds number for surface instability. We use the traditional long-wave expansion technique implemented for investigating the linear stab…
[Phys. Rev. E 109, 065103] Published Mon Jun 10, 2024
From cavitation to astrophysics: Explicit solution of the spherical collapse equation
Author(s): Danail Obreschkow
Differential equations of the form R̈=−kRγ, with a positive constant k and real parameter γ, are fundamental in describing phenomena such as the spherical gravitational collapse (γ=−2), the implosion of cavitation bubbles (γ=−4), and the orbital decay in binary black holes (γ=−7). While explicit ele…
[Phys. Rev. E 109, 065102] Published Fri Jun 07, 2024
Dynamo action driven by precessional turbulence
Author(s): Vivaswat Kumar, Federico Pizzi, George Mamatsashvili, André Giesecke, Frank Stefani, and Adrian J. Barker
We reveal and analyze an efficient magnetic dynamo action due to precession-driven hydrodynamic turbulence in the local model of a precessional flow, focusing on the kinematic stage of this dynamo. The growth rate of the magnetic field monotonically increases with the Poincaré number Po, characteriz…
[Phys. Rev. E 109, 065101] Published Wed Jun 05, 2024
Comparison of viscoelastic flows in two- and three-dimensional serpentine channels
Author(s): Himani Garg and Christer Fureby
Polymer solutions in the dilute regime play a significant role in industrial applications. Due to the intricate rheological properties of these highly viscoelastic fluids, especially in complex flow geometries, a thorough numerical analysis of their flow dynamics is imperative. In this research, we …
[Phys. Rev. E 109, 055108] Published Wed May 29, 2024
Self-propulsion of a periodically forced shape-deforming submillimeter gas bubble
Author(s): Stephen J. Shaw
The self-propulsion (translational instability) of a gas bubble in a liquid undergoing parametrically induced axisymmetric shape distortion due to being forced by a temporally sinusoidal, spatially constant acoustic field is investigated. Employing a model which accounts for the nonlinear coupling b…
[Phys. Rev. E 109, 055107] Published Fri May 24, 2024
Numerical study of Richtmyer-Meshkov instability in finite thickness fluid layers with reshock
Author(s): Linfei Li, Tai Jin, Liyong Zou, Kun Luo, and Jianren Fan
The evolution of a shock-induced fluid layer is numerically investigated in order to reveal the underlying mechanism of the Richtmyer-Meshkov instability under the effect of a reshock wave. Six different types of fluid layer are initially set up to study the effect of amplitude perturbation, fluid-l…
[Phys. Rev. E 109, 055105] Published Thu May 23, 2024
Extreme statistics and extreme events in dynamical models of turbulence
Author(s): Xander M. de Wit, Giulio Ortali, Alessandro Corbetta, Alexei A. Mailybaev, Luca Biferale, and Federico Toschi
We present a study of the intermittent properties of a shell model of turbulence with statistics of ∼107 eddy turn over time, achieved thanks to an implementation on a large-scale parallel GPU factory. This allows us to quantify the inertial range anomalous scaling properties of the velocity fluctua…
[Phys. Rev. E 109, 055106] Published Thu May 23, 2024
Alignments of triad phases in extreme one-dimensional Burgers flows
Author(s): Bartosz Protas, Di Kang, and Miguel D. Bustamante
We analyze the fine structure of nonlinear modal interactions in inviscid and viscous Burgers flows in 1D, which serve as toy models for the Euler and Navier-Stokes dynamics. This analysis is focused on preferential alignments characterizing the phases of Fourier modes participating in triadic inter…
[Phys. Rev. E 109, 055104] Published Wed May 22, 2024
Transition to plastic regime for Rayleigh-Taylor instability in soft solids
Author(s): Aren Boyaci and Arindam Banerjee
Rayleigh-Taylor instability (RTI) is observed in soft materials that have significant resistance to yield. Estimating the instability threshold is critical to several engineering applications and has been the topic of several studies in past decades. However, limited attention has been given to the …
[Phys. Rev. E 109, 055103] Published Wed May 15, 2024