Article
Mechanics
Zhaodong Ding, Kai Mu, Ting Si, Yongjun Jian
Summary: This study comprehensively investigates the instability characteristic of a viscoelastic jet in a co-flowing gas stream. It clarifies the important role of the non-uniform basic velocity in the instability analysis of viscoelastic jets, as well as the competition between the elastic tension and the coupling term in promoting or stabilizing the jet's instability. Three instability mechanisms are identified through energy budget analysis, and the general features of viscoelastic jet instability are obtained through analyzing the variations of the disturbances' growth rate and phase speed. Theoretical investigation of the transitions of instability modes in parameter spaces is also provided.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Astronomy & Astrophysics
L. Norenius, M. Hamrin, O. Goncharov, H. Gunell, H. Opgenoorth, T. Pitkanen, S. Chong, N. Partamies, L. Baddeley
Summary: Studies show that localized dynamic pressure pulses in the magnetosheath, or jets, can impact the magnetopause and be observed as geoeffective elements at ground level. Ground-based magnetometers (GMAGs) detect fluctuations in the geomagnetic field due to impacting jets, with amplitudes of 34 nT, frequencies of 1.9 mHz, and damping times of 370 s. The amplitude of GMAG response depends on the parallel length and maximum dynamic pressure of the jet, with longer and higher pressure jets inducing larger amplitude responses.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Moun Meenakshi, Dipanjan Mukherjee, Alexander Y. Wagner, Nicole P. H. Nesvadba, Raffaella Morganti, Reinier M. J. Janssen, Geoffrey Bicknell
Summary: This study uses relativistic hydrodynamic simulations to investigate the ionization effects of jet-interstellar medium interactions on the gaseous galactic disc. The results show that the shocks from the jets can ionize a significant fraction of dense gas in the disc and clear out the central regions for AGN radiation to penetrate. Jets inclined towards the disc plane couple more strongly with the ISM and ionize a larger fraction of gas in the disc. However, AGN radiation is quickly absorbed by the outer layers of dense clouds and has only a weak ionization effect on the disc on a global scale.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Engineering, Environmental
Zhong-Bo Sun, Hai -Long Liao, Li-Hua Wang, Lan Jiang, Xin Zhang, Bao-Ju Wang, Guang-Wen Chu, Yong Luo
Summary: The flow and breakage behaviors of two liquid jets impacting on stainless steel wire mesh were studied using high-speed photography. The impacts resulted in the formation of liquid jets and further breakage into daughter droplets. The impinging angle, liquid initial velocity, mesh number, and liquid jet diameter were found to affect the flow and breakage behaviors. For water-n-hexane jets, a liquid sheet was formed and could undergo marginal or internal breakup. This study provides a theoretical basis for mass transfer enhancement and reactor design in liquid-liquid systems.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Mechanics
Mateus C. Guimaraes, Fernando T. Pinho, Carlos B. da Silva
Summary: A new theory is proposed to describe the conformation state of polymer chains in free turbulent shear flows of viscoelastic fluids. The theory shows the existence of minimum and maximum solvent dissipation reduction asymptotes and four different polymer deformation regimes, based on self-similarity arguments and new scaling relations for the turbulent flux of conformation tensor. In addition, analytical solutions for the self-similar transverse profiles of the conformation tensor components are obtained. The theory is validated through excellent agreement with direct numerical simulations employing the FENE-P rheological model.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2024)
Article
Chemistry, Multidisciplinary
Amal Sebastian, Daniel Lipa, Sylwia Ptasinska
Summary: This study explores the application of atmospheric pressure plasma jet (APPJ) in medicine and its damage to DNA, and predicts the type and extent of DNA damage under different parameters based on a machine learning model, providing important insights into the potential adverse effects of APPJ on biological samples.
Article
Engineering, Mechanical
Guillaume Maitrejean, Denis C. D. Roux, Maxime Rosello, Pascal Jay, Jean Xing, Bruno Barbet
Summary: A mixed experimental-numerical strategy is used to assess the relaxation time measurement of a weakly elastic polymer solution. The relaxation time is determined by comparing the jetting of the polymer solution experimentally and numerically, using a validated numerical approach and a viscoelastic Oldroyd-B model.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Chemical
Zhaolong Ge, Lei Liu, Zhe Zhou, Zhongtan Li, Jianming Shangguan, Chuanfu Shao
Summary: Jet breaking experiments were conducted to investigate the mechanism of hard rocks breaking under three-dimensional stress. The shape of the rock-breaking holes resembled an inverted & omega;. Ground stress had a significant impact on the rock-breaking performance, with the increase of ground stress leading to higher rock strength and a 28.56% decrease in rock-breaking performance. However, at ground stresses above 50 MPa, the rock-breaking performance increased by 20%. The horizontal stress difference concentrated the stress on the pore walls and weakened the cementation between mineral particles, resulting in increased roughness and a 58.85% increase in rock-breaking performance with a 25.56% reduction in energy consumption. These findings provide valuable data and technical support for the jet breaking of hard rock in deep mine construction.
Article
Engineering, Multidisciplinary
Louise Cottier, Guenter Brenn, Marie-Charlotte Renoult
Summary: The study investigates the behavior of a viscoelastic liquid jet through a temporal stability analysis. Two different sets of initial conditions are proposed to close the initial-value problem, with distinctions made between pure deformation and pure impulse configurations. The application of initial conditions on a given liquid jet allows for visualization and comparison between the two configurations.
ATOMIZATION AND SPRAYS
(2021)
Article
Mechanics
Mu-wei Yao, Li-jun Yang, Qing-fei Fu
Summary: This study investigates the impact of surface viscoelasticity on the stability of compound jets and finds that surface elasticity and viscosity can stabilize the jet, but with different underlying mechanisms. Changes in surface viscoelastic parameters on different interfaces affect the growth rate and dominant wavenumber differently, with an increase in surface shear viscosity reducing the influence of surface elasticity on the maximum growth rate. The adoption of a one-dimensional dispersion equation validated the applicability of the model in the vicinity of small wavenumber.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2021)
Article
Astronomy & Astrophysics
Michael D. Smith, Carl Richards
Summary: The Mach number is a crucial parameter in determining the driving properties and impact on the environment of a supersonic jet. Through numerical simulations, we investigate the effects of different Mach numbers and jet overpressures on the flow pattern and shock locations. We also analyze potential observational diagnostics and the energy transferred into the environment.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Ophthalmology
Tamas Somoskeoy, Paritosh Shah
Summary: The study found that the use of navigated retinal laser for laser retinopexy treatment of retinal tears was safe and effective in the majority of cases, with only a few requiring a second session. There were no cases of retinal detachment or other complications observed with the use of this laser system.
Article
Mechanics
Hanul Hwang, Parviz Moin, M. J. Philipp Hack
Summary: A novel mechanism for amplifying distortions to the material interface of liquid jets has been identified. This mechanism is independent of flow instability and can intensify small perturbations by several orders of magnitude, potentially faster than modal mechanisms like the Kelvin-Helmholtz instability. The mechanism is related to the Orr mechanism and involves reorienting perturbations to amplify material interface distortions.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Astronomy & Astrophysics
Brian Punsly, Hiroshi Nagai, Tuomas Savolainen, Monica Orienti
Summary: The recent development of global millimeter-band very long baseline interferometry (VLBI) has revealed the morphology of the base of the nearby bright extragalactic radio jets in M87 and 3C 84, showing surprising results compared to jet theory predictions. The complex nucleus of 3C 84 appeared as a double or triple nucleus in different observations with varying resolutions. The emergence of east-west double nucleus and the associated separation speed have also been studied, suggesting a predominantly east-west separation speed that persists over a considerable distance from the central supermassive black hole gravitational radius.
ASTROPHYSICAL JOURNAL
(2021)
Article
Mechanics
B. Dinesh, R. Narayanan
Summary: The Rayleigh-Taylor instability of a linear viscoelastic fluid overlying a passive gas is studied, with consideration of key dimensionless groups such as the Bond number and the Weissenberg number. The analysis reveals the branching behavior under different stability conditions, showing the transition from supercritical saturated waves to subcritical breakup. The results suggest that the behavior of the fluid is influenced by factors such as shear modulus and boundary width, leading to either stable waves or unstable breakup patterns.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
B. Neel, E. Villermaux
JOURNAL OF FLUID MECHANICS
(2018)
Article
Physics, Fluids & Plasmas
Baptiste Neel, Ignacio Rondini, Alex Turzillo, Nicolas Mujica, Rodrigo Soto
Correction
Mechanics
B. Neel, H. Lhuissier, E. Villermaux
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
B. Neel, H. Lhuissier, E. Villermaux
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
B. Neel, L. Deike
Summary: The study investigates the effect of surfactant on air bubbles evolving at the water surface, finding that low contamination leads to broad surface size distribution due to bubble coalescence, while higher surfactant concentrations prevent coalescence and increase bubble lifetime, resulting in a surface size distribution identical to the bulk distribution.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Geosciences, Multidisciplinary
B. Neel, M. A. Erinin, L. Deike
Summary: Understanding the physico-chemical conditions of bubble bursting on the production of aerosols is crucial. This study experimentally demonstrates that the coupling between the chemical properties of contaminated water and the physical mechanism of droplet production during bubble bursting controls the efficiency of aerosol production, revealing an optimal production regime at intermediate contamination. This fundamental research paves the way for improved predictions of aerosol production in contaminated water.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Daniel J. Ruth, Baptiste Neel, Martin A. Erinin, Megan Mazzatenta, Robert Jaquette, Fabrice Veron, Luc Deike
Summary: In this study, we experimentally investigate the depth distributions and dynamics of air bubbles entrained by breaking waves using high-resolution imaging and three-dimensional bubble tracking. We find that the bubble concentration decays exponentially with depth below the wave troughs. Additionally, we discover that the flow field induced by the breaking waves enhances the transport of bubbles, which is relevant for the transport of bubbles, oil droplets, and microplastics at the ocean surface.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
M. A. Erinin, B. Neel, D. J. Ruth, M. Mazzatenta, R. D. Jaquette, F. Veron, L. Deike
Summary: Laboratory measurements were conducted to study the characteristics of droplet size, velocity, and accelerations generated by mechanically and wind-forced water breaking waves. The results showed that the droplet size distribution followed power laws, and the velocity and acceleration distributions were found to be asymmetric.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Physics, Fluids & Plasmas
B. Neel, L. Deike
Summary: This study investigates the mechanisms and velocity-size relationships of droplet production from bursting bubbles in both single and collective settings. The experimental results show that droplets from collective bubble bursting have slower velocities and are more scattered compared to those from single bubble bursting.
PHYSICAL REVIEW FLUIDS
(2022)