Article
Mechanics
Majid Rodgar, Helene Scolan, Jean-Louis Marie, Delphine Doppler, Jean-Philippe Matas
Summary: The study experimentally examined the behavior of a bubble injected into a horizontal liquid solid-body rotating flow, showing how factors such as bubble size, rotation speed, and buoyancy impact the bubble's aspect ratio and movement. The study also found that at certain extreme conditions, such as when the Reynolds number exceeds 3000, the bubble can experience abrupt transitions and potentially break up due to resonance between the periodic forcing of the rotating cell and the eigenmodes of the stretched bubble.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Declan B. Gaylo, Kelli Hendrickson, Dick K. P. Yue
Summary: This study focuses on the evolution of the bulk bubble-size distribution under the influence of turbulence-induced fragmentation and free-surface entrainment, finding two regimes based on the entrainment distribution dependence. The weak injection regime is independent of the entrainment distribution, while the strong injection regime's power-law slope is determined by gamma.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Kuan-Ling Huang, Kuo-Long Pan
Summary: The transition between coalescence and bouncing in droplet impacts is influenced by complex interactions of multiple mechanisms, with controlling parameters such as droplet diameter, fluid viscosities, and surface tension. Observations in experiments show different behaviors of various fluids under atmospheric conditions, highlighting the impact of droplet diameter on the occurrence of coalescence and bouncing.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Edward Beaty, John R. Lister
Summary: When two small fluid drops are close enough, the van der Waals force overcomes surface tension and initiates coalescence. The dynamics can be divided into two regimes: Stokes and inertial-viscous, characterized by the forces that balance the van der Waals attraction. The subsequent dynamics in the inertial-viscous regime is self-similar as contact is approached, with the gap width and deformed region decreasing with time.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Huadan Xu, Xinjin Ge, Tianyou Wang, Zhizhao Che
Summary: In this study, the coalescence of two immiscible droplets on a partial wetting surface is explored experimentally and theoretically. The coalescence process is divided into three stages and the impact of immiscible interface on the process is investigated. The study provides insights into the time scales and force interactions involved in the coalescence of immiscible droplets.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Lukas Weimar, Luyang Hu, Tobias Baier, Steffen Hardt
Summary: This study investigates the impact of drops on a porous surface with high contact-angle hysteresis and gas discharge. Four different impact modes of the drops on the surface, ranging from complete repulsion to fast immobilization, are identified and mapped based on the pressure difference of the gas and the impact Weber number. The most notable aspect of the dynamics is the transformation of a drop into a bubble, which occurs when the drop overcomes the repulsion by the gas flow and wets the surface. The transition to the regime where a drop is transformed into a bubble is well described by a simple scaling relationship based on the balance between inertia and the repulsive force due to the gas flow.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Ryan McGuan, R. Candler, H. P. Kavehpour
Summary: This paper investigates the phenomenon of partial coalescence in a viscous quiescent medium using a liquid metal alloy. The study observes the bouncing of coalescing droplets on the interface and develops models to predict droplet velocity, position, and maximum bounce height.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Someshwar Sanjay Ade, Pavan Kumar Kirar, Lakshmana Dora Chandrala, Kirti Chandra Sahu
Summary: We investigated the morphology and size distribution of satellite droplets resulting from the interaction of a water droplet with a swirling airstream. We found that the droplet exhibited different phenomena depending on the strength of the swirl. In the high-swirl scenario, disintegrations of the nodes, rim, and bag-film contributed to smaller satellite droplets, while in the low-swirl case, the breakup of the rim and nodes resulted in larger droplets. Our results also showed that the volume-weighted droplet size distribution had two peaks for low swirl strength and three peaks for high swirl strength.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
C. R. Constante-Amores, A. Batchvarov, L. Kahouadji, S. Shin, J. Chergui, D. Juric, O. K. Matar
Summary: This study investigates the impact of surfactants on drop-interface coalescence dynamics through full three-dimensional direct numerical simulations, highlighting the crucial role of Marangoni stresses in the flow physics of coalescence. Surfactant-laden cases were found to stiffen the interface compared to surfactant-free cases, providing insight into the observed surfactant-induced phenomena.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Yanju Wei, Zhiqiang Mu, Yajie Zhang, Yajing Yang, Shenghua Liu, Chung K. Law, Abhishek Saha
Summary: This study reports the dynamics and morphology of a droplet passing through a soap film, providing experimental observation and theoretical explanation. The study identifies four sequential responses of the film during the process, and develops physical models and analytical expressions to reveal the underlying physics.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Ashik Ullah Mohammad Masuk, Ashwanth K. R. Salibindla, Rui Ni
Summary: The experimental study focuses on investigating the breakup mechanisms and probability of Hinze-scale bubbles in turbulence. By tracking both bubbles and surrounding tracer particles, the researchers quantified the breakup probability of bubbles close to the Hinze scale and analyzed different breakup mechanisms. The study also provides models linking turbulence characteristics, bubble deformation, and Weber numbers, ultimately offering a unique way to extract the breakup probability of bubbles near the critical Hinze scale.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Daniel B. Shaw, Luc Deike
Summary: An experimental study was conducted on bubble coalescence at an air-water interface, examining the evolution of underwater neck and surface bridge. The research explored a wide range of Bond numbers to compare gravity and capillary forces, finding different behaviors for nearly spherical bubbles with Bo << 1 and non-spherical bubbles with Bo > 1. By observing inertial-capillary growth and using a simple oscillatory model, the study characterized the dynamics of both the bubble neck and upper surface in various Bond number scenarios.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Ocean
Arman Ghanavati, Sajad Khodadadi, Mohammad Hassan Taleghani, Mofid Gorji-Bandpy, Davood Domiri Ganji
Summary: In this study, the motion and interaction of a bubble pair rising in a stationary liquid were simulated using the volume of fluid method (VOF). Results showed that four different types of interactions, including coalescence, bouncing, zigzagging, and breakup, can occur between the bubble pair based on the Bond (Bo) and Morton (Mo) numbers. The velocity and drag force of the trailing bubble were found to depend on the separation distance between the bubbles and the wake effect of the leading bubble. A general criterion based on dimensionless numbers was proposed to determine the type of interaction between the bubble pair.
APPLIED OCEAN RESEARCH
(2023)
Article
Mechanics
Dege Li, Haoren Li, Guodong Yang, Yi Cao, Bingfang Huang, Xinlei Wu, Qiang Sun, Chi Ma, Yu Zhou, Yonghong Liu, Yanzhen Zhang
Summary: This study proposes a confined interface vibration inkjet printing technique that allows for printing patterns in a liquid environment with smaller droplet sizes. By adjusting the intensity of the pulse stimulation, the size and quantity of the dispensed droplets can be controlled, enriching the fundamental theory of inkjet printing in liquid phase.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Zhikun Xu, Tianyou Wang, Zhizhao Che
Summary: This study experimentally investigated the breakup process of particle-laden droplets in airflow. The results showed that particles have a heterogeneous effect on the breakup process, accelerating the fragmentation of the liquid film and promoting localized rapid piercing. A correlation length was proposed to characterize the concentration fluctuation scale during the breakup process, and the scaling results agreed well with experimental data.
JOURNAL OF FLUID MECHANICS
(2023)
Review
Chemistry, Physical
Ivan U. Vakarelski, Fan Yang, Sigurdur T. Thoroddsen
Summary: The outcome of bubble collision is determined by hydrodynamic interaction forces, influenced by the tangential mobility of gas-liquid interfaces. Bubbles with mobile surfaces coalesce easier due to lower hydrodynamic resistance, resulting in stronger rebound from a mobile liquid interface with lower viscous dissipation.
CURRENT OPINION IN COLLOID & INTERFACE SCIENCE
(2022)
Article
Energy & Fuels
Yuan Si Tian, Zi Qiang Yang, Sigurbur T. Thoroddsen, Ehab Elsaadawy
Summary: The separation of water droplets from water-in-crude-oil emulsions is crucial in the petroleum industry. A new experimental method involving optical-access flow, Near-Infrared laser illumination, and high-speed video imaging can help select the optimal demulsifier concentration by quantifying coalescence probability.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Ivan U. Vakarelski, Kenneth R. Langley, Fan Yang, Sigurdur T. Thoroddsen
Summary: This study examines the accuracy of numerical simulations in predicting the dynamics of thin liquid film drainage during the collision of bubbles or droplets. Experimental investigations of millimetric bubbles colliding with a flat glass interface in pure water were compared with numerical simulations using the open source Gerris flow solver. The simulation results showed excellent agreement with experimental observations in terms of the bounce trajectory and thin liquid film profile. The study highlights the potential of numerical simulations in resolving the complex processes of high velocity bubble and droplet collisions.
Article
Chemistry, Multidisciplinary
Adair Gallo, Nayara H. Musskopf, Xinlei Liu, Ziqiang Yang, Jeferson Petry, Peng Zhang, Sigurdur Thoroddsen, Hong Im, Himanshu Mishra
Summary: Recent research on the formation of hydrogen peroxide (H2O2) in water microdroplets has attracted significant attention. The presence of ozone (O-3) in the air has been found to have the most significant impact on H2O2 formation in these water microdroplets. Increased gas-liquid surface area facilitates the conversion of O-3 into H2O2.
Article
Engineering, Chemical
Yuan Si Tian, Er Qiang Li, Ehab Elsaadawy, Jia Ming Zhang, Ivan U. Vakarelski, Sigurdur T. Thoroddsen
Summary: In this study, microfluidic techniques were used to investigate the coalescence dynamics of water-in-oil emulsions in a simple shear flow. Experimental results showed a strong correlation between the coalescence time and the droplet approach velocity, effective diameter, offset, and continuous-phase viscosity. A scaling law for the dimensionless time needed for coalescence was also revealed.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Mechanics
Han Li, Han Chen, Er-Qiang Li, Chun-Yu Zhang, Hang Ding
Summary: The impact of a millimetric superhydrophobic sphere on a water pool covered by a thin oil layer is experimentally investigated. The interfacial tension and viscosity of the oil layer are found to significantly affect the fate of the impacting spheres, determining whether they sink or float.
Article
Nanoscience & Nanotechnology
Yi Lu, Shibin Krishna, Che-Hao Liao, Ziqiang Yang, Mritunjay Kumar, Zhiyuan Liu, Xiao Tang, Na Xiao, Mohamed Ben Hassine, Sigurdur T. Thoroddsen, Xiaohang Li
Summary: This article introduces a method for transferring Ga2O3 thin film to arbitrary flexible and adhesive tape, enabling vertical and flexible configurations of electronic devices. Vertical photodetectors fabricated using this method demonstrate good optoelectronic performance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Mechanics
Lei Wang, Marie-Jean Thoraval
Summary: This study numerically investigates the dynamics of a drop containing a bubble impacting onto a pool of the same liquid. It is found that the bubble can only be engulfed into the pool within a limited range of impact velocities and bubble sizes, otherwise it bursts during impact.
Article
Mechanics
Xurui Zhang, Zhen Jian, Boyu Hou, Marie-Jean Thoraval
Summary: The dynamics of water droplet impacting on a soap bubble on a solid substrate are experimentally investigated. Two regimes are discovered at high impact velocities, depending on the size of the soap bubble. The bursting of the soap bubble is attributed to two identified mechanisms.
Article
Mechanics
Yuan Si Tian, Zi Qiang Yang, Sigurdur T. Thoroddsen
Summary: Fast microjets can be produced when drop-impact craters rebound or when a bubble bursts, and they play a crucial role in climate and olfactory senses as a source of aerosols. The most unique and fastest jets are generated when a small dimple forms at the crater bottom and rebounds without pinching off a small bubble. High-resolution numerical simulations reveal a new focusing mechanism that explains the extreme sensitivity to initial conditions observed in experiments of this phenomenon.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Materials Science, Multidisciplinary
Esraa Fakeih, Andres A. Aguirre-Pablo, Sigurdur T. Thoroddsen, Khaled N. Salama
Summary: This study investigates the design and fabrication of porous microneedles (MNs) and finds that injection through porous MNs results in a broader diffusion spread compared to hollow MNs. Three different designs of porous MNs with a constant pore size and controlled pore locations are fabricated using two-photon polymerization (2PP), and factors such as diffusion spread, mixing capabilities, and mechanical resilience are examined. The results show that porous MNs can cover 16 times the injection area of hollow MNs and demonstrate good mixing capabilities and mechanical strength.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Mechanics
Farrukh Kamoliddinov, Ivan U. Vakarelski, Sigurdur T. Thoroddsen, Tadd T. Truscott
Summary: In this experimental study, we investigated the hydrodynamics of a buoyant sphere accelerated along an air-water interface. The sphere displayed different behaviors depending on its speed, from floating on the surface to oscillating underwater and generating air cavities. These underwater air cavities were attached to the sphere surface near the laminar flow separation point. By changing the pulling angle and counterweight-induced velocity, we explored the effects on the hydrodynamics. Additionally, we analyzed the complex fluid-solid interactions and the influence of the air cavity on drag and lift coefficients and overall sphere hydrodynamics, particularly above the critical Froude number of 1.2.
Article
Mechanics
Yangyu Duan, Weiwei Zhao, Chunchun Chu, Yumeng Feng, Song-Chuan Zhao, Marie-Jean Thoraval
Summary: In this study, the impact dynamics of a solid-liquid compound drop on a solid surface was investigated experimentally. It was found that the separation threshold between the particle and the drop varies with the viscosity of the liquid, and the shifting of the particle before impact can induce an inclination in the vertical liquid jetting.
Article
Chemistry, Physical
Zi Qiang Yang, Peng Zhang, Meng Shi, Ali Al Julaih, Himanshu Mishra, Enzo Di Fabrizio, Sigurdur T. Thoroddsen
Summary: Polymer filaments have important applications in biology, tissue engineering, and molecular machines. Researchers have developed a simple method to deposit stretched polymer fibers between micro-pillars, allowing for characterization of filament-forming configurations and their properties.
Article
Physics, Fluids & Plasmas
Ahmed Al Brahim, Sigurdur T. Thoroddsen
Summary: This study focuses on the dynamical rearrangement of a multilayer fluid in a Hele-Shaw cell, and observes various dynamics of stirring and breakthrough. The study reveals that air can break through a high viscosity layer and erupt as a hemisphere into a lower-viscosity layer, accompanied by high-speed airflow. Using high-speed video, the details of the eruptions and the key roles of wetting, contact lines, and three-dimensionality are characterized. Additionally, the study finds counterflows in the center-of-mass trajectories and the interchangeability of top and bottom layers through intermediate layers.