Article
Physics, Fluids & Plasmas
Jie Chen, Aiguo Xu, Dawei Chen, Yudong Zhang, Zhihua Chen
Summary: The two-dimensional Rayleigh-Taylor instability in compressible flow with intermolecular interactions is analyzed using the discrete Boltzmann method. The effects of interfacial tension, viscosity, and heat conduction on the instability are investigated. It is observed that interfacial tension has varying influences on perturbation amplitude, bubble velocity, and entropy production rates at different stages of the instability. Viscosity and heat conduction are found to inhibit the instability.
Article
Engineering, Chemical
Shixing Chen, Enle Xu, Xianliang Meng, Guoguang Wu, Xiaofeng Jiang
Summary: This study reports the pinch-off dynamics and initial deformation of a particle-loaded bubble in various liquids. The relative size and position of the particle with respect to the bubble, as well as the liquid properties, jointly affect the pinch-off process. The particle loading can hinder or promote the pinch-off process, resulting in different pinch-off exponents.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Mechanics
Vatsal Sanjay, Detlef Lohse, Maziyar Jalaal
Summary: In this study, the phenomenon of a rising bubble reaching the liquid-air interface in a yield-stress fluid was numerically investigated. Viscoplasticity was found to play a significant role in controlling the fate of capillary waves and their interaction at the bottom of the cavity, with the free surface converging to a non-flat equilibrium shape once the driving stresses fell below the yield stress. The dynamics and energy budgets of the flow were discussed, leading to the establishment of a regime map with four main regimes exhibiting different characteristic behaviors.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Environmental
H. Wang, P. R. Brito-Parada
Summary: This study provides a detailed investigation on microparticle-laden bubbles rising in water from nozzles, revealing that microparticles reduce the apparent surface tension of the bubble interface and influence its shape deformation and oscillations. High-speed photography allowed the systematic study of two regimes for the first time, showing that microparticles increase the damping rate of the dominant harmonic during shape oscillations.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Mechanics
Maziyar Jalaal, Boris Stoeber, Neil J. Balmforth
Summary: This study examines the spreading of a droplet of yield-stress fluid over a thin film of the same material, presenting scaling laws for the final radius and conducting numerical simulations and experiments to validate the theoretical model.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
K. R. Protsenko, V. G. Baidakov
Summary: Based on molecular dynamics simulations of a stretched Lennard-Jones liquid near the triple point temperature, the possibilities and limitations of classical nucleation theory approximations were analyzed. The nucleation rate, critical bubble radii and work of formation, and nucleus diffusion coefficient were calculated for systems with 5 x 10( 3) to 3 x 10( 5) particles using methods such as direct forward flux sampling, seeding, and well-tempered metadynamics. Surface free energy, sizes, and shapes of critical bubbles were determined from the obtained data. The asymptotic laws of nucleation parameters behavior near the spinodal of a stretched liquid are discussed.
Article
Mechanics
S. Akbari, S. M. Taghavi
Summary: In this study, the injection of a viscoplastic fluid into a quiescent Newtonian medium is investigated experimentally, highlighting the different flow patterns and the effects of governing dimensionless numbers. The research focuses on analyzing detailed flow features and sub-regimes, presenting results versus key dimensionless numbers for application in oil and gas well processes and 3D printing technologies.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Chemistry, Physical
Lyudmila Bel'skaya, Denis Solomatin
Summary: The study confirmed the impact of surface tension on the characteristics of IR spectra using saliva as an example, and identified specific combinations of characteristics related to surface tension.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Engineering, Chemical
M. W. L. Chee, G. Ghasemi, M. A. Rashid, R. R. Fernandes, D. I. Wilson
Summary: The removal of thick layers of viscoplastic soft-solid food-related materials from PMMA plates using water jets was studied. The removal process involved the growth of a circular crater when the layer thickness was small, and the formation and rupture of a blister followed by cratering when the layer thickness was thick. The blister formation process could be described by simple geometric models.
JOURNAL OF FOOD ENGINEERING
(2023)
Article
Thermodynamics
Lucas Farias Severo, Flavia Schwarz Franceschini Zinani, Luiz Alberto Oliveira Rocha
Summary: This study applies the Constructal Design Method to investigate a row of circular tubes subjected to cross-flows of visco-plastic Bingham fluids, finding that the dimensionless heat transfer density increases with the Bejan number but decreases with the Bingham number. Additionally, the optimal step distance between tubes decreases with the increase in the Bejan number, but increases with the increase in the Bingham number.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Multidisciplinary Sciences
Virgile Thievenaz, Alban Sauret
Summary: At large scales, particulate suspensions flow like homogeneous viscous liquids, but at the particle scale, the role of local heterogeneity brought by the particles cannot be neglected. The volume fraction also matters, as particulate effects can be present in dense suspensions across distances much larger than the particle diameter. Therefore, the behavior of a suspension depends on the scale at which it is observed.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biochemical Research Methods
Yangchao Zhou, Meihang He, Haitao Zhang, Bohua Liu, Chongling Sun, Ziyu Han, Xuexin Duan
Summary: We propose a nozzle-free acoustic-based method for generating droplets with diameters ranging from 2 to 1800 mu m using a gigahertz (GHz) bulk acoustic wave (BAW). This method is versatile, scalable, and compatible with handling viable samples.
Article
Physics, Fluids & Plasmas
Yu-Chuan Cheng, Ting-Heng Hsieh, Jih-Chiang Tsai, Tzay-Ming Hong
Summary: Researchers have found through experiments that balloons can take on multiple shapes, including straight, necking, wrinkled, helix, and supercoil, depending on the twist angle and ratio of length to diameter. The phase diagram of balloons is affected by their twisting history, and the positions of different phases can be adjusted by changing the twist angle and initial length.
Article
Mechanics
Michael Krieg, Kamran Mohseni
Summary: This study presents a methodology to identify the conditions necessary for a vortex ring to separate from a shear flow by analyzing the relationship between characteristic velocities of the jet and the vortex ring along the symmetry axis. A strategy for determining these characteristic velocities purely from the jet driving programs is introduced, and the relationship between pinch-off and the characteristic velocities is validated through various jet driving conditions. The study confirms that the new centerline velocity criterion closely coincides with vortex ring pinch-off, establishing it as a predictive tool.
Article
Chemistry, Physical
Mattia Carneri, Davide Ferraro, Afshin Azarpour, Alessio Meggiolaro, Sebastian Cremaschini, Daniele Filippi, Matteo Pierno, Giuliano Zanchetta, Giampaolo Mistura
Summary: The use of highly slippery lubricated surfaces can facilitate the movement of high-viscosity YSF droplets. The droplets slide on the lubricated surfaces and roll down when their descending speed increases, especially at high inclinations and low concentrations.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(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)
