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Control of chaos in Darcy–Bénard axisymmetric convection in a cylindrical enclosure using a uniform vertical cross-flow Phys. fluids (IF 4.6) Pub Date : 2024-03-15 C. Kanchana, P. G. Siddheshwar, D. Laroze
The linear and weakly nonlinear stability analyses of Darcy–Bénard convection of a Newtonian fluid experiencing a uniform vertical cross-flow is investigated in the paper for various aspect ratios. Making use of the Maclaurin series representation, an expression for axial eigenfunctions is obtained with the radial eigenfunction being a Bessel function of first kind. These eigenfunctions are influenced
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Performance evaluation and enhancement of turbulent flow and convective heat transfer characteristics for turbine blade internal cooling Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Ben-Xi Zhang, Li-Qian Wang, Wei Lu, Jiang-Hai Xu, Yi-Bo Wang, Yan-Ru Yang, Xiao-Dong Wang
For turbine blade internal cooling, the performance of turbulent flow and convective heat transfer in the cooling channel is numerically investigated via the computational fluid dynamics method, where the cooling channel adopts the combination of transverse rib arrangements and round-edged rib configurations or the combination of oblique rib arrangements and round-edged rib configurations. Under these
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Particulate dispersion in turbulent wake of Ahmed body and experimental investigation of impact of rear slant angle Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Manish K. Mathur, Murali R. Cholemari, Srinivas V. Veeravalli
This study investigates the particle dispersion characteristics in the turbulent wake of a simplified vehicle model (Ahmed body) for two values of the rear slant angle ϕ (25° and 40°) to study the effect of flow separation. In the experiments (Reynolds number Rel=1.90 ×105), smoke particles were released from a source and visualized with a laser sheet. Concentration fields were analyzed to calculate
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On reduced-order modeling of gas–solid flows using deep learning Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Shuo Li, Guangtao Duan, Mikio Sakai
Reduced-order models (ROMs) have been extensively employed to understand complex systems efficiently and adequately. In this study, a novel parametric ROM framework is developed to produce Eulerian–Lagrangian simulations. This study employs two typical parametric strategies to reproduce the physical phenomena of a gas–solid flow by predicting the adequate dynamics of modal coefficients in the ROM:
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Wettability alteration of quartz sand using Z-type Langmuir–Blodgett hydrophobic films Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Baghir A. Suleimanov, Hakim F. Abbasov
This paper presents the results of a study of the effect of sand treatment on its filtration and wetting properties by applying Langmuir multimolecular film coatings of fatty acids. It has been established that the coefficient of water filtration through sand treated with a 2% solution of stearic acid in chloroform is reduced by 82%. It is shown that a change in the filtration properties of sand is
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Controlled transport of fluid particles by microrotors in a Stokes flow using linear transfer operators Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Jake Buzhardt, Phanindra Tallapragada
The manipulation of a collection of fluid particles in a low Reynolds number environment has several important applications. As we demonstrate in this paper, this manipulation problem is related to the scientific question of how fluid flow structures direct Lagrangian transport. We investigate this problem of directing the transport by manipulating the flow, specifically in the Stokes flow context
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Influence of embedded structure on two-phase reactive flow characteristics for a small combustion chamber with a moving boundary Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Yongtao Wang, Xiaobing Zhang
In special launch scenarios such as armament and aerospace, the scale of the launch system is severely restricted, which causes unstable combustion of propellant. An embedded structure for the small propulsion system driven by solid propellant is proposed to overcome this problem. This study aims to demonstrate the two-phase flow behaviors and launch safety of the combustion chamber with an embedded
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Predicting shear stress distribution on structural surfaces under internal solitary wave loading: A deep learning perspective Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Miao Zhang, Haibao Hu, Binbin Guo, Qianyong Liang, Fan Zhang, Xiaopeng Chen, Zhongliang Xie, Peng Du
The density of the ocean varies unevenly along the vertical axis. In the presence of external disturbances, internal solitary waves (ISWs) are generated. The strong shear flow field induced by ISW seriously threatens the operational safety of marine structures. Therefore, it has become a hot spot to study the force law of marine structures in ISW. The existing studies are conducted when the ISW parameters
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A lattice Boltzmann model for incompressible gas and liquid two-phase flows combined with free-surface method Phys. fluids (IF 4.6) Pub Date : 2024-03-15 Yilin Liu, Dongke Sun, Zexin Zhang, Wei Chen
A novel lattice Boltzmann (LB) model is proposed to study the gas and liquid two-phase flows with large density and viscosity ratios. In the model, both the gas and liquid phases are considered as viscous incompressible fluids, which are governed separately by the two-relaxation-time LB equations. They are coupled by a momentum exchange method at the interface. The interaction between the gas and liquid
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Flow control by dielectric barrier discharge plasma actuators for a rectangular jet with inlet disturbance Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Keunseob Lee, Satoshi Kikuchi
Direct numerical simulations were performed to examine the control mechanism of a plasma actuator using a dielectric barrier discharge in a rectangular jet with an inlet disturbance. The nozzle has a ratio of 75–10 mm, while the Reynolds number is 3300, and the peak frequency near the nozzle exit is 55 Hz. The jet is controlled by the actuators with conditions of 55 Hz burst frequency, 10% duty ratio
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Cracking process and microstructural characteristics of granite under heating–cooling alternations Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Kun Long, Qike Wei, Kang Peng, Yang Wu, Song Luo, Yugang Cheng, Lei Li
Studying the damage correlation mechanism of rocks subjected to heating–cooling alternations is of important significance for deeply understanding the permeability increase mechanism of reservoirs during heat extraction from hot dry rocks and assessing the reservoir stability. By carrying out the uniaxial compression test, Brazilian splitting test, nuclear magnetic resonance test, and scanning electron
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Impact of flow intermittency on heat transfer enhancement in serpentine channels Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Guanqing Xiong, Zhaoguang Wang
With liquid cold plates being widely applied in industries such as battery energy storage systems, advanced heat transfer enhancement technologies are urgently needed to efficiently dissipate the ever-increasing heat load. The present work numerically and experimentally explores the potential of flow intermittency in a laminar serpentine channel for thermal performance improvement. The numerical analysis
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Solving Euler equations with gradient-weighted multi-input high-dimensional feature neural network Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Jiebin Zhao, Wei Wu, Xinlong Feng, Hui Xu
The study found that it is difficult to capture the solutions at the shock wave and discontinuity surfaces when solving Euler equations using physics informed neural network. Thus, this paper proposes an improved neural network based on adaptive weights for multi-input high-dimensional features to solve the Euler equations. First, adaptive weights regarding the velocity are added to the control equation
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Modification of magnetorheological fluid and its compatibility with metal skeleton: Insights from multi-body dissipative particle dynamics simulations and experimental study Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Yingtao Sun, Zhenhua Wei, Jianfeng Zhou, Aiqin Mao, Di Bian
Magnetorheological fluid (MRF), as a smart material, plays a pivotal role in sealing equipment. However, the interfacial compatibility between MRF and metal significantly impacts the adhesion of the two phases, which subsequently determines the sealing performance of MRF once it is used as a sealing medium. However, the interface mechanism and dynamical magnetic migration performances between MRF and
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A perturbation approach to study the shock wave propagation in a non-ideal magnetogasdynamics under isothermal condition Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Shalini Yadav, Deepika Singh, Rajan Arora
The main goal of this paper is to obtain a global solution to the problem of imploding strong cylindrical shock waves (SWs) collapsing at the axis of symmetry in a non-ideal gas under the influence of an axial magnetic field using the perturbation series technique. This global solution is valid for the entire flow field up to the instant of collapse. Guderley's asymptotic solution, which is only applicable
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Peristaltic transport of viscoelastic fluid in curved ducts with ciliated walls Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Aamar Abbasi, Sherjeel Danish, Waseh Farooq, M. Ijaz Khan, Mehdi Akermi, Hala A Hejazi
The transport of complex rheological fluids in physiological ducts is often facilitated by the dynamic phenomenon of peristalsis. Additionally, peristaltic transport assisted by cilia plays a significant role in various natural processes such as respiration, circulation, locomotion, and reproduction. This study focuses on magnetically induced flow bounded by non-uniform curved walls, motivated by the
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Aeroelastic characteristics of flexible membrane wings with ceiling effect Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Guojun Li, Rajeev Kumar Jaiman, Biao Lei, Hongzhong Liu
We present a numerical study to analyze the aeroelastic characteristics of two-dimensional flexible membrane wings subjected to the ceiling effect. A body-fitted variational aeroelastic solver based on the fully coupled Navier–Stokes and nonlinear structural equations is employed to model the coupled fluid-membrane system. The coupled dynamics and the aerodynamic performance of flexible membrane wings
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Outlet boundary condition and mean temperature gradient effects on the minimum acoustics disturbances energy in triggering nonlinear thermoacoustic instability Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Xinyu Zhao, Dan Zhao, Cody M. Shelton, Bing Wang, Xu Dong, Junwei Li, Yue Huang
In this study, we theoretically investigate the impact of outlet boundary conditions and mean temperature gradients on the maximum transient growth rate of acoustical energy and the critical energy required for triggering. Our analysis encompasses open–open and open–closed thermoacoustic systems. The theoretical models developed focus on horizontal ducts with a mean temperature jump over the heat source
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The effect of temperature on the pressure energy distribution in the process of near-wall single bubble collapse Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Guohui Zhao, Wei Xu, Jian Wang, Yuanyuan Zhao, Fujian Zhao, Xiuli Wang
At the interface between rotating components and the working medium in fluid machinery, cavitation in the liquid is induced. The temperature of the working medium has a significant influence on the cavitation. However, the effect of temperature on the pressure and pressure energy in the collapse of bubbles cannot be explained accurately. This study established cavitation models containing insoluble
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Effect of slip-induced fluid inertial torque on the angular dynamics of spheroids in a linear shear flow Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Zhiwen Cui, Huancong Liu, Jingran Qiu, Lihao Zhao
The angular dynamics of tiny spheroidal particles in shear flows have been widely investigated, but most of the studies mainly focus on the effect of strong shear, while the combined effect of both shear and slip velocity at the center of the particle has been less considered. Actually, the fluid inertial torque induced by the slip velocity between particle and fluid plays a significant role in spheroid
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Numerical study on the onset of global-scale flow from individual buoyant plumes: Implications for indoor disease transmission Phys. fluids (IF 4.6) Pub Date : 2024-03-14 Chao-Ben Zhao, Jian-Zhao Wu, Bo-Fu Wang, Tienchong Chang, Quan Zhou, Kai Leong Chong
Transport of exhaled droplets and aerosol suspension is a main route for the transmission of highly infectious respiratory diseases. A poorly ventilated room, where human body heat drives the flow and the pathogen motion, is one such paradigmatic situation with an elevated risk of viral transmission. Here, we report a numerical study on human body heat-driven buoyancy convection in a slender rectangular
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Manipulation of the flow induced by afterbody vortices using sweeping jets Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Xiaodong Chen, Shan Zhong, Tanghong Liu, Ozgun Ozer, Guangjun Gao
In this study, the impact of oscillatory fluids on the flow induced by afterbody vortices, resembling those of a high-speed train, was investigated in wind tunnel experiments. The afterbody vortices were generated by a cylindrical model with a slanted base at Reynolds numbers ranging from 87 000 to 200 000. A fluidic oscillator was utilized to produce sweeping jets (SWJ) acting on the vortical flow
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High-amplitude pressure pulsations induced by complex inter-blade flow during load rejection of ultrahigh-head prototype pump turbines Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Xiaolong Fu, Deyou Li, Jingwei Lv, Biao Yang, Hongjie Wang, Xianzhu Wei
The flow pattern evolution is particularly complicated in the low specific speed impeller of ultrahigh-head pump turbines. To reveal the mechanism of pressure pulsation induced by the inter-blade flow, the load rejection process of an ultrahigh-head prototype pump turbine was numerically calculated using one- and three-dimensional coupled compressible flow simulation methods. The mechanism of pressure
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Droplet electrohydrodynamic deformation in a shear flow field Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Guanqiu Hao, Le Lv, Wei Yu, Xiangdong Liu, Yongping Chen
The electrohydrodynamic deformation characteristics of a leaky dielectric droplet in combined shear flow field (SFF) and electric field (EF) are investigated by a three-dimensional numerical simulation. Based on the investigation, the cooperation and competition of the two fields on the droplet electrohydrodynamic deformation degree D and orientation angle ϕd are revealed. The influences of SFF strength
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Gas dynamics at starting and terminating phase of a supersonic exhaust diffuser with a conical nozzle Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Sina Afkhami, Nematollah Fouladi
This research investigates the process of starting and breakdown of second throat diffuser during high-altitude test of conical nozzle with a high expansion ratio. The subscale experimental setup includes a conical nozzle with an expansion ratio of 53, plus a second throat diffuser with a contraction ratio of 1.85, using compressed air as the working fluid. Numerical simulation has been employed to
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Accelerated evolution of Burgers' turbulence with coarse projective integration and deep learning Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Mrigank Dhingra, Omer San, Anne E. Staples
The evolution of a turbulent flow to a statistically steady state can be cast as a multiscale problem involving energy redistribution processes that take place on the long, large eddy turnover timescale and chaotic processes that take place on the much shorter timescale of the turbulence fluctuations. But the absence of a way to perform super-resolution reconstructions of the instantaneous velocity
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New higher-order accurate super-compact scheme for three-dimensional natural convection and entropy generation Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Ashwani Punia, Rajendra K. Ray
Exploring natural convection in three dimensions through numerical analysis has become essential for gaining a deeper understanding of this process compared to studying it in just two dimensions. This paper presents an enhanced analysis of three-dimensional (3D) natural convection phenomena within an air-filled cubical cavity, with a primary focus on heat transfer characteristics. The distinguishing
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Flow dynamics of a liquid–liquid bi-swirl injector Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Vishnu Natarajan, Umesh Unnikrishnan, Jeong-Yeol Choi, Vigor Yang
This work presents detailed two-phase flow simulations of liquid–liquid bi-swirl injectors for engineering applications. Liquid oxygen and kerosene are delivered into the injector, which is initially filled with air. A parametric study is conducted on the recess length of the inner tube to investigate its effect on the flow dynamics and spray pattern. The simulations are performed using an improved
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Dielectrophoretic–inertial microfluidics for Symbiodinium separation and enrichment Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Teng Zhou, Jixin He, Zhihao Wu, Qin Bian, Xiaohan He, Shizheng Zhou, Juncheng Zhao, Tao Wu, Liuyong Shi, Hong Yan
In the marine environment, the symbiotic relationship between Symbiodinium and corals plays a pivotal role in coral growth and development. Against the backdrop of widespread coral bleaching due to the global climate change, the facile and efficient separation and enrichment of different strains of Symbiodinium hold significant importance for studying coral bleaching. This paper aims to report a platform
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Analytical solution for the submerged free jet Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Avishai Oved, Herman D. Haustein
Laminar submerged free jet theory still falls short in the near-nozzle region and transition to Schlichting's self-similar jet. The author's recent solution, based on mass conservation, is found lacking beyond the near-nozzle jet-core region. Instead, it is here constrained to conserve momentum, resulting in a locally linearized convection-diffusion equation, valid over jet width and up to self-similarity
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Effect of turbulent coflows on the dynamics of turbulent twin jets Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Farzin Homayounfar, Babak Khorsandi, Susan Gaskin
The impact of turbulent coflows on the dynamics of turbulent twin round jets is investigated experimentally. Parallel twin jets, at three jet spacing values and two Reynolds number/jet-to-coflow velocity ratios, were released into turbulent coflows with two distinct levels of turbulence intensity. Velocity measurements were made using acoustic Doppler velocimetry. An increase in the coflow turbulence
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Study on water entry into shallow-water current using smoothed particle hydrodynamics method Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Ke Zhao, Sheng-Fa Yang, Fu-Ren Ming, Pei-Yin Yuan
Water entry is a typical problem in shipbuilding and ocean engineering. When the ship entering shallow-water current, the combined effects of current and water bottom will complicate the fluid field and further affect the hydrodynamic responses of the ship. In this paper, a two-dimensional bow section entering shallow-water current is studied by smoothed particle hydrodynamics method and the accuracy
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Investigation of the role of charge injection and Coulomb force during the melting of phase-change materials under constant temperature boundary conditions Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Ahmed Hassan, James S. Cotton
This paper presents an investigation of the melting of dielectric material in a rectangular cavity under the effect of electrohydrodynamics (EHD). First, phase-change modeling is implemented to simulate the melting performance of paraffin wax without EHD under constant temperature boundary conditions until a steady-state condition is achieved. Next, the whole set of coupled EHD equations is introduced
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Physical simulation study on production characteristics and mechanism of connate water in gas reservoirs Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Mengfei Zhou, Xizhe Li, Yong Hu, Xuan Xu, Chang He, Hongming Zhan, Yize Huang
The late-stage development of gas reservoirs often encounters the paradox of significant remaining formation pressure coupled with low wellhead pressure, which indicates small drainage volume, low gas production rate, and low recovery efficiency, reducing gas supply and economic benefit. Owing to the lack of experimental research, the reasons behind this contradiction between gas production and producing
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Free convection in a differentially heated square cavity filled with low-Prandtl-number materials: Numerical studies using transition shear stress transport model Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Satyajit Das Karmakar, Prasun Dutta, Himadri Chattopadhyay
Computing the flow field under free convection in a cavity becomes particularly challenging for low-Prandtl-number (Pr) fluids typically encountered for liquid metals. The objective of the present study is to investigate the natural convection process in a differentially heated square cavity employing the transition shear stress transport (SST) model for the Prandtl number Pr∈[0.001,0.1] and the Rayleigh
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Vortex synchronization-enabled heat-transfer enhancement in a channel with backward- and forward-facing steps Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Yuan Ma, Feng Ren, Hui Tang, Chenglei Wang
A channel with one backward-facing step and one forward-facing step is a typical configuration in engineering applications. In the channel, good heat transfer performance is often required, and the enhancement is usually achieved by employing different passive control methods, such as modification of geometric configuration or application of nanofluid. However, the other control method, i.e., active
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Discrete element analysis on impact failure mechanism of “Zhengzhou 7.20” catastrophic flood for coal gangue railway subgrade Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Xianquan Li, Lianwei Ren, Xinming Chen, Quanwei Yang
Limited research has been conducted on the failure mechanism of coal gangue railway subgrade structures during catastrophic flood disasters, including the impact of varying flood impact heights and load sizes. This study investigates the process and mechanism of coal gangue railway subgrade failure in the coal mining subsidence area, in conjunction with the “7.20” catastrophic flood in Zhengzhou. First
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Thermo-hydrodynamic lubrication and energy dissipation mechanism of a pump-turbine thrust bearing in load-rejection process Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Jingwei Cao, Yongyao Luo, Liwei Deng, Xin Liu, Shu Yan, Liming Zhai, Zhengwei Wang
The dynamic behavior of the pump-turbine thrust bearing is important to the safety operation of the unit. This paper analyzed the lubrication and energy dissipation mechanism of pump-turbine thrust bearing during load-rejection based on the thermo-hydrodynamic model. The results show that the variation of the axial force and the maximum pad surface pressure is basically consistent with that of the
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The effect of contact angle hysteresis on a droplet in a viscoelastic two-phase system Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Kazem Bazesefidpar, Outi Tammisola
We investigate the dynamic behavior of a two-dimensional droplet adhering to a wall in Poiseuille flow at low Reynolds numbers, in a system where one of the phases is viscoelastic represented by a Giesekus model. The Cahn–Hilliard Phase-Field method is used to capture the interface between the two phases. The presence of polymeric molecules alters the viscoelastic drop's deformation over time, categorizing
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Stability of low-pressure turbine boundary layers under variable Reynolds number and pressure gradient Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Alessandro Dotto, Matteo Luzzi, Jacopo Verdoya, Daniele Simoni, Ardeshir Hanifi, Jan Oscar Pralits
The free-stream turbulence induced transition occurring under typical low-pressure turbine flow conditions is investigated by comparing linear stability theory with wind tunnel measurements acquired over a flat plate subjected to high turbulence intensity. The analysis was carried out, accounting for three different Reynolds numbers and four different adverse pressure gradients. First, a non-similarity-based
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An experimental investigation on the ice-breaking phenomenon induced by the spark-generated bubble near a vertical plate Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Qianqian Dong, Qiyang Chen, Chengwang Xiong, Shiping Wang
The present work experimentally studied the coupled interaction between the fracture of an ice plate floating on the water surface, induced by the pulsation of a high-pressure bubble, and the associated deformation of a vertically submerged aluminum plate. The dynamic behaviors of bubbles and fractured ice were concurrently recorded using two high-speed cameras, and the plastic deformation of the aluminum
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Enhancing numerical accuracy in the prediction of rotor wake vortex structures Phys. fluids (IF 4.6) Pub Date : 2024-03-13 Andrew Bodling, Clemens Schwarz, C. Christian Wolf, Anthony D. Gardner
In modern high-fidelity computational fluid dynamic simulations, the primary vortex system in hover often breaks down into secondary vortices. The sources of numerical error influencing the prediction of the vortex system were studied by performing high-fidelity simulations of the wake of a two-bladed rotor and comparing the predictions to stereoscopic particle image velocimetry measurements in different
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Effects of body shape on hydrodynamic interactions in a dense diamond fish school Phys. fluids (IF 4.6) Pub Date : 2024-03-12 John Kelly, Haibo Dong
To examine the effect that body shape plays in the interactions between fish in a dense fish school, fish-like undulating foils are numerically studied in a high-density diamond school. Shape parameters of leading edge radius, boattail angle, and maximum thickness location along the body are independently varied to control the body shape. A traveling wave is prescribed to the body, and the flow around
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Formation and propagation characteristics of a weak shock wave in maglev tube Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Kai-Wen Wang, Xiao-Hui Xiong, Chih-Yung Wen, Guang Chen, Xi-Feng Liang, Hua-Kun Huang, Jia-Bin Wang
The propagation of the weak shock wave (WSW) to the tunnel exits and their radiation as micro-pressure waves (MPWs) may cause sonic booms or structural resonance of buildings, posing potential hazards to humans, animals, and buildings in the exit's environment. The characteristics of the WSW and sonic booms of a maglev train/tube coupling model were studied based on the two-dimensional axisymmetric
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On interaction between a bubble with evaporation and heated pillar block in microchannel Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Haoxiang Huang, Jialing Yu, Zhe Yan, Zhenhai Pan
As demand for managing high heat flux in specialized applications grows, flow boiling in microchannels has received escalating attention for its high efficiency and cost-effectiveness. The complex interaction between an evaporating bubble and a heated pillar in a microchannel is governed by a confluence of transport mechanisms, including bubble morphology, fluid convection, heat transfer, and phase
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Optimizing unconventional gas extraction: The role of fracture roughness Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Yapeng Wang, Yongli Zhang, Xinle Yang, Jinling Dong, Yulin Ma
In unconventional reservoir engineering, such as coalbed methane and shale gas extraction, fracture behavior is pivotal in gas accumulation, migration, and extraction, acting as a primary channel for gas flow. Current research inadequately addresses the quantitative impact of fracture roughness on gas extraction. In this study, we introduce a novel interdisciplinary model that quantitatively characterizes
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The droplet race: Optimization of a wettability gradient surface Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Graham Danny Koyeerath, Yann Favennec, Bruno Auvity, Christophe Josset
Droplet behavior influenced by wettability distribution is a pertinent field of research with applications in lab-on-a-chip and heat transfer devices among others. Some have proposed patterned surfaces with controlled variation of wettability to orient the direction of the droplet motion or to increase its velocity. These patterns are arrived upon with experience and knowledge of this phenomenon. In
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Influence of hydrophobic particles on the film drainage during bubble–solid interaction Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Palash Dhara, Buyoung Jung, Luigi Davide Gala, Suraj Borkar, G. G. Fuller
In this article, we investigate the complex drainage behavior of liquid (“dimple”) films entrapped between hydrophilic glass substrates and air bubbles in water and aqueous suspensions of polystyrene (PS) particles. The film drainage was monitored by capturing the evolution of spatial-temporal thicknesses using interferometry. Faster drainage of the entrapped film is observed in the PS colloid suspensions
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A physics-guided machine learning framework for real-time dynamic wake prediction of wind turbines Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Baoliang Li, Mingwei Ge, Xintao Li, Yongqian Liu
Efficient and accurate prediction of the wind turbine dynamic wake is crucial for active wake control and load assessment in wind farms. This paper proposes a real-time dynamic wake prediction model for wind turbines based on a physics-guided neural network. The model can predict the instantaneous dynamic wake field under various operating conditions using only the inflow wind speed as input. The model
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Particle-in-cell/Monte Carlo collision simulation on gap breakdown characteristics of under the conditions of hot-electrode and high-temperature gas medium in low-voltage circuit breaker chamber Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Lijun Wang, Runze Hu, Zhuo Chen, Zhiwei Wang
The gas composition inside the low-voltage circuit breaker (LVCB) chamber and the residual plasma in the post-arc stage affect the breakdown process, which in turn affects the breaking capacity of LVCBs. In this paper, the back-arc breakdown and post-arc re-breakdown phenomena occurring inside the LVCB chamber are categorized as the breakdown in the case of high-temperature gas gap of hot electrodes
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Optimization of multi-staged Tesla valve using response surface methodology Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Pengju Li, Yinghan Liu, Qingguo Wen, Zhengkai Zhang, Yawen Ma, Jianwei Zhu
The multi-stage Tesla valve (MSTV), which consists of multiple identical TVs in series, enhances the effectiveness of the TV. To further improve the performance of the MSTV, an improved MSTV has been proposed by designing each arch channel in the typical MSTV as two separate arch channels: the inner arch channel and the outer arch channel. Response surface methodology is used to optimize the improved
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Behavior of small water droplets in a highly viscous flow in a converging and diverging channel Phys. fluids (IF 4.6) Pub Date : 2024-03-12 D. Shayunusov, D. Eskin, H. Zeng, P. A. Nikrityuk
Understanding the evolution of water droplets moving in a highly viscous bulk flow (e.g., bitumen) has attracted increasing attention in the context of numerous separation technologies due to various issues relating to the environment (re-use of water) and engineering failures (corrosion of pipelines). With this in mind, the main objectives of this work are to explore the dynamics of water droplets
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Comparison of flow characteristics of plane jet impingement on a solid plate and on a sand bed Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Jieyun Mao, Jin-Hua Si, Guidong Li, Xikun Wang
As compared to the well-researched case of a plane jet impinging on a solid plate, relatively rare attention was paid to the impingent on an erodible sand bed, which induces continuous bed transformations and interactively affects the jet development. The present study measured the flow of an impinging plane jet on a solid plate and on an erodible sand bed, respectively, by using particle image velocimetry
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Deformation characteristics of a ring-stiffened cylindrical shell induced by shock waves and coalesced bubbles in double-charge underwater explosions Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Yifan Zhang, Liangtao Liu, Jinxiang Wang, Teng Ma, Kun Liu, Xiwen Chen
This study investigates the deformation characteristics of a ring-stiffened cylindrical shell induced by shock waves and coalesced bubbles in double-charge underwater explosions. A numerical model for coupling underwater multi-point explosion loads with the cylindrical shell is established by the Arbitrary Lagrange Euler method, and underwater explosion experiments with double charges are also conducted
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Experimental investigation of characteristics of turbulence induced by multiple oscillating grids Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Qijun Li, Nian-Sheng Cheng
Experiments were conducted to systematically investigate the nearly homogeneous turbulence generated by multiple oscillating grids. Altogether 54 runs were completed by employing five different grids. For each run, four to nine layers of grids were installed, which were operated with different frequencies, strokes and grid spacings. The particle image velocimetry was used to obtain flow velocity characteristics
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Mixed convection of a viscoplastic fluid with a variable yield stress in a lid-driven cavity Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Danial Rezaee, Alireza Samari, Amirreza Azad
This study is a numerical investigation on heat and momentum transfer in viscoplastic fluids that exhibit a variable yield stress. Viscoplastic fluids are recognized for transitioning from solid to liquid under flow-induced shear-rate. However, these materials exhibit intricate rheological behaviors beyond this fundamental characteristic, often linked to thixotropy. Thixotropy delineates reversible
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Experimental investigation of flow patterns and rheological characteristics of compressed air foam in horizontal tube Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Hongsheng Li, Songyong Liu, Cuijun Jin, Panpan Xu, Juan Wang, Qizhi Xie
The use of compressed air foam (CAF) for fire suppression has undergone rapid development in recent years. It has been successfully applied in fire incidents in the petroleum and chemical industries. The increasing need to fighting fires at high elevations necessitates an understanding of the rheological characteristics, pressure gradient changes, flow characteristics, and regularities of CAF within
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Cavitation in a binary Lennard–Jones mixture: van der Waals gradient theory and molecular dynamics simulation Phys. fluids (IF 4.6) Pub Date : 2024-03-12 V. G. Baidakov, V. M. Bryukhanov
The size dependence of the surface tension of critical bubbles in a superheated (stretched) Lennard–Jones solution with complete solubility of the components is considered. Two approaches are used to determine this dependence. The first one is based on the van der Waals gradient theory, and the second one is based on molecular dynamic simulation results of nucleation in a solution. It is established
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Experimental study on contact time of a water droplet impact under controlled surface temperature Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Shu-Rong Gao, Qi-Hui Jia, Shi-Hua Shi, Zhe Liu, Bo-Jian Wei, Yi-Feng Wang, Shao-Fei Zheng, Yan-Ru Yang, Xiao-Dong Wang
Bouncing droplets on superhydrophobic surfaces is one of the potential methods used for anti-icing. The surface supercooling is a significant parameter influencing the bouncing dynamic. A droplet impacting cold superhydrophobic surfaces is investigated via experimental methods. The influence of the surface supercooling and the Weber number on the impact dynamic is elucidated. Intriguingly, the surface
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Analysis of axial force and pressure pulsation of centrifugal pump as turbine impeller based on dynamic mode decomposition Phys. fluids (IF 4.6) Pub Date : 2024-03-12 Peixuan Li, Wei Dong, Haoqing Jiang, Haichen Zhang
To investigate the spatiotemporal evolution mechanism of the axial force on a centrifugal pump acting as a turbine, this study focuses on a single-stage single-suction centrifugal pump and applies dynamic mode decomposition (DMD) to decompose the flow field of the turbine impeller's axial force. The axial force of the impeller under three flow conditions, namely, 1.0Qd, 1.3Qd, and 1.6Qd, is extracted