New Papers in Fluid Mechanics

Comparison of viscoelastic flows in two- and three-dimensional serpentine channels

Physical Review E - Wed, 05/29/2024 - 11:00

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

Polydisperse particle-driven gravity currents propagating into a stratified ambient in containers of general cross sections

Physical Review Fluids - Tue, 05/28/2024 - 11:00

Author(s): T. Zemach

We investigate high-Reynolds-number polydisperse gravity currents propagating along a channel of general cross-section into a linearly stratified ambient fluid. We formulate and solve numerically the shallow water equations and present typical height and velocity profiles of the current and particle mass concentration. Two dimensionless parameters, Stratification (S) and particle buoyancy (Π), are relevant. Increasing S decreases the current velocity propagation, but as Π increases, the current propagates faster. For a specific S, Π dependence, an equilibrium occurs for a significant time and the system behaves like a system without particles propagating into the ambient of constant density.


[Phys. Rev. Fluids 9, 054105] Published Tue May 28, 2024

Turbulent drag reduction in water-lubricated channel flow of highly viscous oil

Physical Review Fluids - Tue, 05/28/2024 - 11:00

Author(s): Alessio Roccon, Francesco Zonta, and Alfredo Soldati

The transportation of oil through pipelines and channels is a highly energy-intensive operation, primarily due to the significant viscosity of the oil and the consequent high friction. Among the various friction reduction methods utilized in this domain, the water-lubricated approach has emerged as particularly promising. Our investigation focuses on assessing the efficacy of this technique through direct numerical simulations of turbulent channel flow. In this setup, we introduce two thin water layers near the walls, which serve to lubricate the flow of oil within the core.


[Phys. Rev. Fluids 9, 054611] Published Tue May 28, 2024

Dynamics of soap bubble inflation

Physical Review Fluids - Tue, 05/28/2024 - 11:00

Author(s): Saini Jatin Rao, Siddhant Jain, and Saptarshi Basu

Often considered a childhood pastime, soap bubbles emerged as a captivating domain for rigorous scientific inquiry for generations. While blowing soap bubbles is familiar to everyone, the underlying physics of inflating them remains unanswered. In our investigation, we visualize the previously unexplored internal airflow experimentally, revealing a toroidal vortical flow that resembles a bound vortex ring. The air enters the bubble as a round jet, emerging from the nozzle opening and impinges on the expanding concave interior to form this toroidal vortex. We also predict several scaling laws for the inflation rate and dynamics of this confined vortical flow by varying the source pressure.


[Phys. Rev. Fluids 9, L051602] Published Tue May 28, 2024

Microfluidic droplet pinch-off modified by hard and soft colloids: A scaling transition

Physical Review Fluids - Tue, 05/28/2024 - 11:00

Author(s): Loïc Chagot, Simona Migliozzi, and Panagiota Angeli

In this Letter, we explore the influence of colloids at liquid-liquid interfaces on droplet pinch-off dynamics in microfluidic devices. We uncover a significant deviation in droplet formation time compared to pure systems, similarly to surfactant-laden systems. Yet notably, colloids exert minimal impact on droplet size, indicating potential nonlinear effects. The dynamics of neck thinning without colloids agree with the classic pendant drop scaling laws, while particle presence replaces traditional viscous and inertial-viscous regimes with a single power law, suggesting an elastic behavior driven by soft particle interactions.


[Phys. Rev. Fluids 9, L052201] Published Tue May 28, 2024

Self-propulsion of a periodically forced shape-deforming submillimeter gas bubble

Physical Review E - Fri, 05/24/2024 - 11:00

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

Mesoscopic lattice Boltzmann modeling of dense gas flows in curvilinear geometries

Physical Review Fluids - Thu, 05/23/2024 - 11:00

Author(s): Sergiu Busuioc

This paper derives the Enskog equation in the context of orthonormal vielbein fields, allowing the use of arbitrary coordinate systems to describe spatial geometry. Additionally, an adapted coordinate system in momentum space is employed, which is connected to physical space via vielbeins. A suitable finite-difference lattice Boltzmann model is developed and validated against a direct simulation Monte Carlo particle-based method for solving the Enskog equation in curvilinear geometries. The test scenarios include cylindrical Couette and Fourier flow between coaxial cylinders, and spherical Fourier flow between concentric spheres.


[Phys. Rev. Fluids 9, 053401] Published Thu May 23, 2024

Mean temperature scalings in compressible wall turbulence

Physical Review Fluids - Thu, 05/23/2024 - 11:00

Author(s): Cheng Cheng and Lin Fu

We report a new Mach number invariant function for the mean temperature field in compressible wall turbulence. We demonstrate its validation by comparing it with the invariant functions derived in the previous studies, i.e., the semi-local-type and van-Driest-type scalings, case by case. The newly proposed temperature transformations based on the new scaling show an improvement in channel flows over adiabatic walls and supersonic/hypersonic turbulent boundary layers with cold walls. The effects of the generated high-order terms during derivation are also clarified. These findings may be revealing for the development of the near-wall model in high-speed aerodynamics.


[Phys. Rev. Fluids 9, 054610] Published Thu May 23, 2024

Numerical study of Richtmyer-Meshkov instability in finite thickness fluid layers with reshock

Physical Review E - Thu, 05/23/2024 - 11:00

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

Physical Review E - Thu, 05/23/2024 - 11:00

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

Physical Review E - Wed, 05/22/2024 - 11:00

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

Electroconvection in electrodeposition: Electrokinetic regularization mechanisms of shortwave instabilities

Physical Review Fluids - Wed, 05/22/2024 - 11:00

Author(s): I. Rubinstein and B. Zaltzman

Dendrite formation resulting from morphological instability in cathodic electrodeposition of a metal and, especially, the role that related fluid flows play, has long been of major interest to physicists. We focus on the physical mechanisms behind: (1) Underlimiting currents: Selection of electrokinetic-reactive length scale, which is the geometric average of the electric double layer width and the reaction-diffusion length defined as the ratio of cation diffusivity to electrode reaction rate; (2) Overlimiting currents: Domination of emerging electroconvective flow, selecting the cathodic diffusion layer width as dominant length scale for morphological instability and emerging dendrites.


[Phys. Rev. Fluids 9, 053701] Published Wed May 22, 2024

Rheology of granular mixtures with varying size, density, particle friction, and flow geometry

Physical Review Fluids - Wed, 05/22/2024 - 11:00

Author(s): Eric C. P. Breard, Luke Fullard, and Josef Dufek

This work studies the rheology of dense granular media, exploring the effects of varying particle size, density, friction and shear profiles across different flow regimes. Utilizing the discrete element method (DEM), the research extends current models by integrating volumetric contributions and introducing a new power-law scaling that unifies local and nonlocal rheology data onto a single master curve. This approach bridges the μ(I)-rheology and Kinetic Theory, offering a framework for predicting the behavior of granular flows in various settings, from geophysical flows to industrial processes.


[Phys. Rev. Fluids 9, 054303] Published Wed May 22, 2024

Self-similarity in single-point turbulent statistics across different quadrants in turbulent rotor wakes

Physical Review Fluids - Wed, 05/22/2024 - 11:00

Author(s): Xue-Lu Xiong (熊雪露), Shujin Laima (赖马树金), Hui Li (李惠), and Yi Zhou (周毅)

We present a self-similarity analysis of single-point turbulent statistics across different quadrants in turbulent wakes. We show here that within the wake self-similar region, the distribution of the Reynolds shear stress in different quadrants can also attain a state of self-similarity. The length scaling is the same for the Reynolds shear stress and its different quadrant contributions, while there exists a difference in velocity scaling. There exists a strong connection between ejection events and large-scale coherent structures, as well as deceleration extreme events.


[Phys. Rev. Fluids 9, 054608] Published Wed May 22, 2024

Investigations of skin friction drag mitigation over viscoelastic surfaces in supersonic flows

Physical Review Fluids - Wed, 05/22/2024 - 11:00

Author(s): Soumen Chakravarty and V. Narayanaswamy

This article presents the first ever systematic demonstration of the drag reduction at supersonic speed regime caused by non-rigid surfaces prepared using compliant viscoelastic coating. This work lays the foundation to a new engineering paradigm that fuses engineered surfaces to create positive aerodynamic outcomes at speeds that are relevant to aerial vehicles.


[Phys. Rev. Fluids 9, 054609] Published Wed May 22, 2024

Editorial: Coauthor! Coauthor!

Physical Review Fluids - Tue, 05/21/2024 - 11:00

Author(s): Randall D. Kamien and Daniel Ucko

[Phys. Rev. Fluids 9, 050001] Published Tue May 21, 2024

Wall modes and the transition to bulk convection in rotating Rayleigh-Bénard convection

Physical Review Fluids - Tue, 05/21/2024 - 11:00

Author(s): Xuan Zhang, Philipp Reiter, Olga Shishkina, and Robert E. Ecke

Wall modes and bulk modes compete in small-aspect-ratio rapidly rotating Rayleigh-Bénard convection. Wall modes remain robust in the presence of bulk convection and contribute substantially to the global heat transport.


[Phys. Rev. Fluids 9, 053501] Published Tue May 21, 2024

Experimental collisions of varying roughness wetted particles in the pendular regime compared to numerical simulations

Physical Review Fluids - Tue, 05/21/2024 - 11:00

Author(s): Oscar J. Punch, Daniel J. Holland, Andreas Baumann, and Peter Eberhard

Numerical simulations of wet particles often use the particle roughness as a minimum separation criterion to limit the viscous force. Here we investigate the validity of this through a comparison of experiments of binary wet particle collisions to numerical discrete element method (DEM) and smoothed particle hydrodynamics (SPH) simulations.


[Phys. Rev. Fluids 9, 054302] Published Tue May 21, 2024

Exit dynamics of a sphere launched underneath a liquid bath surface

Physical Review Fluids - Fri, 05/17/2024 - 11:00

Author(s): Xiaofeng Wei, Dege Li, Jing Lei, Jinglu Li, Javier Rivero-Rodríguez, Fangye Lin, Dongyun Wang, and Benoit Scheid

In this paper, we investigate the exit dynamics of a sphere launched underneath a liquid bath surface at a prescribed impact velocity. Spheres with radii approximate or smaller than the capillary length are considered. The process can be sequenced into a partial exit stage that forms a coated layer, and a full exit stage with an attached ligament. A bouncing-off regime, a lower pinch-off penetration regime, and an upper pinch-off penetration regime are identified, separating by a penetration Weber number and a switching Weber number. The phase diagram is revealed, where the two critical Weber numbers are functions of the Bond number.


[Phys. Rev. Fluids 9, 054003] Published Fri May 17, 2024

Transition to plastic regime for Rayleigh-Taylor instability in soft solids

Physical Review E - Wed, 05/15/2024 - 11:00

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

Pages

Subscribe to www.nonequilibrium-turbulence.org.uk aggregator