Article
Mechanics
Niklas Hidman, Henrik Stroem, Srdjan Sasic, Gaetano Sardina
Summary: This paper provides a comprehensive explanation for the lift force acting on a freely deformable bubble rising in a linear shear flow, and presents four distinct flow mechanisms and their associated vorticity dynamics. Theoretical framework and numerical simulations are used to support the explanations. The study also highlights the importance of considering the shear rate in modeling the lift force.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Jie Zhang, Ming-Jiu Ni, Jacques Magnaudet
Summary: Highly resolved simulations were used to study the buoyancy-driven motion of two identical gas bubbles released in a liquid at rest. Two distinct evolutions were observed depending on the values of Galilei (Ga) and Bond (Bo) numbers, with the bubbles either moving in a side-by-side motion or with the trailing bubble drifting laterally. Bubble deformation played a key role in determining the system's evolution.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Alessio Innocenti, Alice Jaccod, Stephane Popinet, Sergio Chibbaro
Summary: The study investigates bubble-induced turbulence through numerical simulations, comparing results with experiments and previous simulations to assess the accuracy of the model. Analysis reveals that the energy transfer mechanisms and potential cascades are unveiled through a local scale-by-scale analysis in physical space.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Jie Zhang, Ming-Jiu Ni, Jacques Magnaudet
Summary: This study numerically investigates the dynamics of gas bubbles released in line under highly inertial conditions. Depending on the ratios of buoyancy, viscous and capillary forces, the bubbles can either rise independently or continue to interact and possibly collide. The shape of the bubbles and the initial distance between them play a crucial role in determining their trajectories.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Tian Ma, Bernhard Ott, Jochen Frohlich, Andrew D. Bragg
Summary: Data from direct numerical simulations show that bubbles in disperse bubbly flows in a vertical channel have a significant impact on carrier-phase turbulence. Bubbles enhance anisotropy in the flow, alter the direction of energy transfer, and affect the nonlinear term and intermittency of the dissipation range.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Niklas Hidman, Henrik Strom, Srdjan Sasic, Gaetano Sardina
Summary: Using direct numerical simulations (DNS), a transition in the scalar spectra from k(-5/3) to k(-3) scaling with wavenumber k is observed in bubbly flows with passive scalars. The decay of the scalar spectrum is faster than k-3 at high wavenumbers for cases with a mean scalar gradient in the horizontal direction. DNS computations reveal that scalar fluctuations are produced by the mean scalar gradient at length scales above the bubble diameter, leading to the k(-3) scaling of the scalar spectra.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
J. Ruiz-Rus, P. Ern, V Roig, C. Martinez-Bazan
Summary: This study experimentally investigates the coalescence cascade process of a swarm of deformable bubbles. The stages of the coalescence cascade are characterized by the diameter of the largest bubbles. The collision frequency and coalescence efficiency of different sized bubbles are obtained from the experiments. Models describing the collision frequency for different coalescence regimes are provided.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
F. Le Roy De Bonneville, R. Zamansky, F. Risso, A. Boulin, J. -f. Haquet
Summary: This study presents a numerical method for simulating the flow induced by bubbles rising at large Reynolds numbers and accurately estimates the hydrodynamic force exerted by the liquid on the bubbles. The simulations show good agreement with experimental results, indicating potential applications in studying industrial bubble columns and large-scale systems.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Ashik Ullah Mohammad Masuk, Yinghe Qi, Ashwanth K. R. Salibindla, Rui Ni
Summary: A phenomenological model is proposed to describe the deformation and orientation dynamics of finite-sized bubbles in both quiescent and turbulent aqueous media. By dividing flow inertia into contributions from slip velocity and velocity gradients, a new formulation for bubble deformation is constructed and validated against experiments. The relative importance of each deformation mechanism is measured and suggestions on implementing the framework for characterizing bubble dynamics in simulations are provided.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Wentao Ma, Xuning Zhao, Christine Gilbert, Kevin Wang
Summary: The response of underwater structures to a near-field explosion is investigated in this paper using a two-dimensional model problem. A computational framework that couples a finite volume compressible fluid dynamics solver with a finite element structural dynamics solver is employed. Three different collapse modes are discovered and their causes are visualized through the analysis of fluid pressure and velocity fields, bubble dynamics, and structural deformation. The study also reveals the significant effect of the second pressure pulse resulting from the contraction of the explosion bubble on the collapse of the structure.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Engineering, Marine
Taiji Tanaka, Yoshihiko Oishi, Hyun Jin Park, Yuji Tasaka, Yuichi Murai, Chiharu Kawakita
Summary: The study demonstrated that air lubrication with repetitive bubble injection achieved superior efficiency in drag reduction compared to continuous bubble injection.
Article
Mechanics
Guangzhao Zhou, Andrea Prosperetti
Summary: Taylor bubbles, gas volumes with a diameter larger than the tube in which they rise, exhibit a characteristic bullet shape and ascend at a speed primarily determined by the tube diameter and liquid properties. By limiting the bubble diameter and using a cylindrical 'cage' of thin vertical rods, the flow rate of the liquid film along the bubble surface can be increased, allowing the bubble to ascend significantly faster.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Marine
Trong-Nguyen Duy, Thanh-Hoang Phan, Quang-Thai Nguyen, Seong-Ho Park, Warn-Gyu Park
Summary: This study investigates bubble dynamics with highly nonlinear interactions between an oscillating bubble and gas-liquid interface in the vicinity of a rigid wall with a gas-entrapping hole through numerical simulations. The simulations show that the gas entrapped inside the hole significantly affects the formation and redirection of the liquid jet, as well as the dynamics of the cavitation bubble.
Article
Mechanics
Ebrahim Ghahramani, H. Strom, R. E. Bensow
Summary: Cavitating flows involve vapour structures with various length scales, highlighting the importance of accurately estimating small-scale cavities. A hybrid cavitation model that combines a mixture model with a Lagrangian bubble model has been developed to capture multi-scale dynamics and interactions between vapour structures and the continuous flow. This approach shows considerable improvements in predicting large cavities and capturing small-scale structures, even with lower mesh resolution.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Aditya Madabhushi, Krishnan Mahesh
Summary: We propose a compressible multi-scale model that captures the dynamics of both large vapour cavities and micro-bubbles and takes into account the compressibility of the medium. The model tracks the homogeneous mixture of liquid and resolved vapour in an Eulerian sense and tracks the unresolved vapour in a Lagrangian sense using a novel equation. The model has been validated and shown to accurately capture the collapse of single and multiple bubbles, as well as the interaction between bubbles in a cluster.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Thermodynamics
Stephanie A. Coronel, Jean-Christophe Veilleux, Joseph E. Shepherd
Summary: Experimental study shows that compression waves generated by water hammer events can cause distortion of the water-gas interface and the formation of a two-phase mixture. Despite some ignition events observed, the mixing of water with gas almost completely suppressed the pressure rise during the ignition transient.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Engineering, Chemical
Conor D. Martin, Joseph E. Shepherd
Summary: An experimental study on the low-temperature and low-pressure autoignition of Jet A and surrogate fuels revealed four distinct ignition modes, with the individual hydrocarbon components exhibiting varied ignition behaviors and minimum autoignition temperatures dependent on their molecular structures. The surrogates displayed similar ignition behaviors to Jet A, with the JI mixture proving to be a more suitable substitute in the low-temperature thermal ignition regime.
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
(2021)
Editorial Material
Acoustics
Alan T. Wall, Kent L. Gee, Philip J. Morris, Tim Colonius, K. Todd Lowe
Summary: The goal of this editorial is to highlight the key developments in supersonic jet and launch vehicle noise research over the past several decades, as well as to describe the critical modern requirements facing government and industry organizations. Furthermore, it aims to summarize the contributions of the articles in this Supersonic Jet Noise special issue within the context of these developments and requirements.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Engineering, Electrical & Electronic
Atsuki Hosaka, Yuki Mizushima, Satomi Hamada, Ryota Koshino, Akira Fukunaga, Toshiyuki Sanada
Summary: The contact-type cleaning method, which involves direct contact of impurities with brushes or brush-induced fluid flow, is used for brush scrubbing. When applying brush cleaning to nanosized defects in advanced semiconductor manufacturing, it is important to understand the interaction between the brush and scrubbing surface under actual operating conditions. High-speed photography was used to observe the brush volume ratio and brush nodule deformation near the surface, providing insights into efficient nanosized cleaning.
MICROELECTRONIC ENGINEERING
(2022)
Article
Engineering, Mechanical
Ziyi Su, Kazuaki Inaba, Amit Karmakar, Apurba Das
Summary: Thermal striping in a nuclear power plant can lead to cracks and high cycle thermal fatigue failure in pipes, but the use of functionally graded materials can alleviate this issue. A simulation of ceramic and structural steel functionally graded T pipes under thermal striping was conducted, showing that FGM pipes have a higher fatigue life potential at the T-junction.
INTERNATIONAL JOURNAL OF MECHANICS AND MATERIALS IN DESIGN
(2022)
Article
Chemistry, Analytical
Yuta Matsumoto, Yuki Mizushima, Toshiyuki Sanada
Summary: In this study, we demonstrate a method for removing gas from small holes using acoustic waves. We investigated the mechanism of liquid filling and gas removal in liquids by changing hole size, wettability, and liquid surface tension. Our experimental results show that combining two different frequencies of acoustic waves can completely remove gas in a short period of time. The formation of droplets or films and the approaching and coalescing of gas columns are the dominant mechanisms during the removal process.
Article
Mechanics
M. D. Frederick, R. M. Gejji, J. E. Shepherd, C. D. Slabaugh
Summary: We experimentally observed the density field and reaction structure of methane and natural gas detonation waves propagating in a narrow channel. The instability level, cell size, and chemiluminescence intensity were found to be influenced by nitrogen dilution concentration. The presence of higher hydrocarbons, primarily ethane, in natural gas increased the fine-scale structure of the detonation front and created a more continuous reaction front. Furthermore, we observed the formation and dissipation of material separated across the shear layer behind the front.
Article
Physics, Applied
Masamitsu Kurashita, Akira Fukunaga, Toshiyuki Sanada, Chikako Takatoh
Summary: This study evaluates the phenomena in the interface between a wet PVA sponge and different materials during a chemical mechanical polishing cleaning process. The torques of a rolling wet PVA sponge were measured to determine the effect of surface free energy on the torques between two materials. The results suggest that increasing the rotational speed of a wet PVA sponge decreases some of the torques generated due to hydrogen bonding component interactions.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Mechanics
Ryunosuke Adachi, Kazumichi Kobayashi, Hiroyuki Fujii, Toshiyuki Sanada, Masao Watanabe
Summary: In this study, we investigated the possibility of wetting failure by examining the rim instability of the liquid sheet ejected after a water drop impacted a dry solid surface. This was made possible through the use of an ultra-high-speed camera.
Article
Instruments & Instrumentation
Yoshia Miyachi, Hajime Furuichi, Toshiyuki Sanada, Yuki Mizushima
Summary: In this study, a phase detection method using a film-based optical waveguide was developed, which can measure the simultaneous local multipoint and high temporal resolution phase detection on a smooth surface. The proposed method can diagnose the dispersed two-phase flow near the wall inside of machines or curved tubes.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Engineering, Electrical & Electronic
Shota Suzuki, Yuki Mizushima, Satomi Hamada, Ryota Koshino, Akira Fukunaga, Toshiyuki Sanada
Summary: Research finds that cross-contamination occasionally occurs during the cleaning process in semiconductor manufacturing using polyvinyl acetal (PVA) brushes due to the re-deposition of contaminants. To understand why contamination patterns in the form of nodules still occur even when brushes and surfaces are in relative motion, the contact path of roller brush nodules on a rotating plate was studied. The experimental results showed that the stamped contacts of the nodule shape coincide with the recontamination points, occurring in a certain area on the wafer.
MICROELECTRONIC ENGINEERING
(2023)
Article
Nuclear Science & Technology
Hajime Furuichi, Kenichi Katono, Yuki Mizushima, Toshiyuki Sanada
Summary: This study aims to improve the accuracy of measuring liquid film thickness using an optical waveguide film sensor. The sensor detects light reflection at the liquid film surface with high spatial resolution. A signal processing method is proposed to remove measurement errors caused by the curved surface of the liquid film. Numerical investigation shows that the curved surface has negligible effects on the measurement accuracy up to a certain surface curvature.
NUCLEAR SCIENCE AND ENGINEERING
(2023)
Article
Mechanics
D. T. Schoeffler, J. E. Shepherd
Summary: Normal detonation reflection generates a shock wave that exhibits complicated dynamics. The influence of a finite detonation thickness on the reflected shock has been historically neglected, but simulations show that the reflected shock accelerates to a large speed not predicted by theory. Analysis with a shock-change equation identifies the nonuniform upstream flow as the principal factor for the large shock acceleration. Simulations of detonation reflection demonstrate the impact of finite detonation thickness on the trajectory of the reflected shock.
Article
Polymer Science
Yoshinori Jinbo, Yuki Mizushima, Toshiyuki Sanada
Summary: This study numerically predicted and controlled the flow of liquid film and the distribution of chemical solution on a rotating disk in single wafer processing using the open-source program OpenFOAM. The obtained results agreed with the literature.
JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Anh Viet Pham, Kazuaki Inaba, Miyuki Saito, Masaharu Sakai
Summary: This paper investigates the velocity and temperature performance of a high-aspect-ratio rectangular jet controlled by dielectric barrier discharge plasma actuators. The results demonstrate that the plasma actuators can effectively control the velocity and temperature distributions without the need for additional hardware.