Article
Mechanics
Tingting Li, Zhiwen Cui, Xianxu Yuan, Ying Zhang, Qiang Zhou, Lihao Zhao
Summary: In this study, we conducted direct numerical simulations to investigate the behavior of particle suspensions in compressible turbulent vertical channel flows. We found that the compressibility effect amplifies the mean velocity, fluctuations, and slip velocity of particles in the streamwise direction. Additionally, the wall-normal and spanwise fluctuations of particle velocities are augmented by the compressible effect in the channel core region. The quadrant analysis of fluid fluctuation velocities at particle positions revealed preferential distributions in certain quadrants, indicating the influence of compressible flows on particle wall-normal transport.
Article
Physics, Multidisciplinary
Sukesh Roy, Joseph D. Miller, Gemunu H. Gunaratne
Summary: Studying turbulent flows is challenging due to the lack of high-frequency, high-resolution measurements. Using a burst-mode laser system in experiments can provide insights into small-scale structures and velocity dynamics in turbulent flows.
COMMUNICATIONS PHYSICS
(2021)
Article
Multidisciplinary Sciences
Endao Han, Lailai Zhu, Joshua W. Shaevitz, Howard A. Stone
Summary: In this study, a biflagellated sphere at low Reynolds number is propelled using uniform and static electric fields via Quincke rotation. The Quincke swimmers exhibit three different forms of motion, including a self-oscillatory state due to elastohydrodynamic-electrohydrodynamic interactions. Each form of motion follows a distinct trajectory in space, demonstrating a potential method to control the locomotion of artificial flagellated swimmers.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Luminita Nicoleta Dumitrescu, Eusebiu-Rosini Ionita, Ruxandra Birjega, Andrada Lazea-Stoyanova, Maria-Daniela Ionita, George Epurescu, Ana-Maria Banici, Simona Brajnicov, Florin Andrei, Andreea Matei
Summary: This study presents the deposition of thin films of lamellar clays using laser techniques, focusing on the optimization of deposition parameters to achieve highly oriented crystalline films. The films were characterized using various techniques and different wetting properties were achieved by adjusting the deposition techniques and parameters.
Article
Mechanics
M. Nakad, T. Witelski, J. C. Domec, S. Sevanto, G. Katul
Summary: Sucrose, a main product of photosynthesis necessary for plant growth, is transported through phloem in a process described by the Munch pressure and mass flow model. This study revisits osmotically driven flows by considering the effects of Taylor dispersion on mass transport, which has been overlooked in phloem flow studies. It is shown that Taylor dispersion can enhance sucrose transport by increasing the apparent diffusion coefficient.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Madhusree Kole, Ram Krishna Shah, Sameer Khandekar
Summary: The existing thermal management strategies for mini-/micro scale electronic devices have reached their limits, calling for the development of innovative heat transfer methods. This study investigates a novel heat transfer configuration involving convective heat transfer of two-phase air-ferrofluid Taylor bubble flow in a square mini channel at low Reynolds number. The results show significant improvement in heat transfer coefficient.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Nanoscience & Nanotechnology
Yuqian Gu, Martha Serna, Sivasakthya Mohan, Alejandra Londono-Calderon, Taimur Ahmed, Yifu Huang, Jack Lee, Sumeet Walia, Michael T. Pettes, Kenneth M. Liechti, Deji Akinwande
Summary: The research demonstrated successful synthesis of MoS2 and WS2 on sapphire wafers through a one-step sulfurization method, with the thin films transferred to SiO2/Si substrates. The fabricated MoS2 and WS2 memristors showed stable non-volatile switching and a satisfactory large on/off current ratio. Tuning the sulfurization parameters was found to be a simple and effective strategy to improve the performance of the memristors.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Marine
Kai Zhang, Hongbo Zhu, Yong Cao, Dai Zhou
Summary: This paper presents numerical simulations of the Reynolds number effects on the bistable states of the wake of a wavy cylinder. The results show that the steady vortical structures in state I exhibit low-frequency fluctuations in drag forces with increasing Reynolds number, while state II is characterized by the emergence of another spectral peak in the lift coefficient. The transition to turbulent flows and the streamwise gust flows over the wavy cylinder are also studied.
Article
Engineering, Chemical
Hui Cai, Guoqing Miao
Summary: This study reported the flow pattern in a vertically vibrated, annular, and granular system, showing either laminar granular flow or turbulent granular flow in different vibration modes. The flow patterns were explained and identified using the Reynolds numbers of the granular system. The results revealed a property peculiar to the granular flow similar to, yet different from, viscous fluids.
Article
Mechanics
Jan Martin Nordbotten, Endre Joachim Lerheim Mossige
Summary: This paper addresses a fundamental and unsolved problem in fluid dynamics, which is to determine the behavior of rising bubbles and falling drops of one miscible liquid in another. The authors propose the first theory that predicts the velocity, volume, and composition of these drops at low Reynolds numbers. They derive a universal scaling law when diffusion out of the drop is negligible, and a parameter-free first-order ordinary differential equation when diffusion occurs. The results are validated against experimental data and the drop-scale parameters of the theory are identified.
Article
Materials Science, Ceramics
Rui Pinho, Inigo Bretos, Ricardo Jimenez, M. Lourdes Calzada, Maria J. Hortiguela, Gonzalo Otero-Irurueta, Maxim Ivanov, Alexander Tkach, M. Elisabete Costa, Paula M. Vilarinho
Summary: A major challenge in integrating functional oxides like ferroelectrics into microelectronics and flexible electronics is reducing their processing temperature to a level below the degradation temperature of silicon and flexible plastic substrates. To address this issue, attention has been focused on low-temperature processing of oxide films using chemical solution deposition (CSD). In this study, polycrystalline KNN thin films were successfully fabricated at a low temperature of 400 degrees C using a modified CSD process called the Seeded Photosensitive Precursor Method (SPPM). These films demonstrated monophasic structure, stoichiometric composition, and significant values of remnant polarization and hysteretic piezoresponse, making them suitable for direct integration into high-performance electronic devices.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Energy & Fuels
A. B. Zolotukhin, A. T. Gayubov
Summary: This article investigates the nonlinear effects of fluid flow in a porous medium and proposes a new semi-analytical equation. The equation considers the gas slippage effect and inertial forces, successfully predicting the deviations from Darcy's law in low-permeability media. Core flow experiments validate the equation's accuracy.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Yu Kai Wu, Yan Peng Liu, Mao Sun
Summary: Most smallest flying insects use bristled wings which can reduce drag and side forces compared to flat-plate wings.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
Petr Lazarenko, Vadim Kovalyuk, Pavel An, Sergey Kozyukhin, Viktor Takats, Alexander Golikov, Victoria Glukhenkaya, Yuri Vorobyov, Timur Kulevoy, Aleksey Prokhodtsov, Alexey Sherchenkov, Gregory Goltsman
Summary: Sn doping is an efficient approach to reduce the switching energy of Ge2Sb2Te5, optimize its properties, and enable fully optical multilevel reversible recording.
Article
Mechanics
Lei Dong, Kwing-So Choi, Yaxing Wang
Summary: In this study, the flow control of the tip vortices over a very low aspect-ratio wing was performed using dielectric-barrier-discharge plasma actuators. The results showed that plasma flow control led to significant changes in the aerodynamic forces, with the lift coefficient increasing by 23% and decreasing by 30% with the blowing and suction plasma actuators, respectively. The drag coefficient only experienced a minor change of less than 10%. The blowing plasma actuator moved the tip vortices away from the wing tip, increasing the streamwise vorticity, turbulence intensities, and Reynolds stress. On the other hand, the suction plasma actuator shifted the tip vortices closer to the wing tip. The blowing plasma increased the tip vortex circulation, while the counter-flowing suction plasma reduced it.