Article
Thermodynamics
Yadong Chen, Yuxuan Yang, Xiaoxiao Shi, Wenrui Zhang, Liansheng Liu, Xuanchen Liu
Summary: In this paper, the dynamic evolution of a single drop impacting a horizontal hydrophilic wire is explored through experiments and numerical simulation methods. The movement behavior law of the drop impacting the curved surface is analyzed by combining the phenomena of spreading, retracting, and breaking. Moreover, the effects of eccentricity, Weber number, and wall wettability on drop impact spreading dynamics are studied.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Engineering, Environmental
Jiyizhe Zhang, Joseph D. Berry, Kathryn A. Mumford, Dalton J. E. Harvie, Weiyang Fei, Geoffrey W. Stevens, Yundong Wang
Summary: This study investigated the single drop breakage in a lab-scale reciprocating plate column using experimental observation and numerical simulation. Two breakage mechanisms were identified, mainly due to shear stress and plate wettability. Experimental results showed that breakage probability was influenced by operating conditions, while the number of daughter drops was affected by the energy input.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Physical
Yin Guan, Jingwei Fu, Shuang Wu, Chuanpeng Yu, Xiyang Chen, Cheng Zhou
Summary: This paper investigates the dynamical behaviors of water drop impacting and bouncing on an inclined hydrophobic surface with a numerical method. Several key impacting factors are examined, and scaling laws of the nondimensionalized maximum spreading diameters are discovered, providing a useful supplement to the understanding of post-impacting drop behaviors on an inclined hydrophobic surface.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Chemistry, Multidisciplinary
Zhaochang Wang, Xiaojun Liu, Jiawei Ji, Yunlong Jiao, Kun Liu
Summary: Controlling the generation of air cavities in liquids is crucial for underwater marine systems. Researchers have found that etching a biomimetic microstructure on the surface of spheres can dramatically reduce the critical velocity of air cavity generation, regardless of surface wettability.
Article
Thermodynamics
Yikai Li, Ming Zhu, Ziming Yang, Chenghan Sun, Dongfang Wang, Haiyan Chen, Zhongjie Shi, Gaoran Wei
Summary: This paper investigates the impact of fuel droplets on the piston surface in direct injection diesel engines, which greatly affects the combustion process and emission generation. The dynamic behaviors of droplets impacting on a vertically vibrating plate were experimentally explored to mimic the interaction between droplets and vibrating engine body. The results reveal that the maximum spread time of the inner lamella remains relatively stable, while the overall spreading time depends on the growth time of the rim. The fluctuation range of the growth time of the rim increases with vibrating frequency and decreases with impacting height.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
Manas Ranjan Behera, Anvith Rao, Anirvan Dasgupta, Sudipto Chakraborty
Summary: This study presents a numerical investigation of the impact dynamics and outcomes when a liquid drop impinges on a liquid pool. A regime map is provided to show the outcomes as a function of dimensionless factors. It is found that inertia, surface tension, and viscous forces control these outcomes. The study considers a wide range of Weber numbers (0≤We≤350) and Ohnesorge numbers (0.002≤Oh≤0.020). Based on different morphologies, the outcomes are categorized into two regimes, coalescence and splashing, with three subregimes within them. Phase boundaries between these regimes are quantified and illustrated in We-Oh phase diagrams. The study also identifies eight distinct flow structures and analyzes their characteristics and origins.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Construction & Building Technology
Zhixiang Cao, Ruiping Wang, Chao Zhai, Yi Wang, Tongtong Zhao, Songheng Wu
Summary: The vortex rings ventilation (VRV) system, consisting of vortex rings, reduces the loss of fresh air during transportation. A vortex ring generator with a fresh air cavity is proposed to form confined vortex rings and improve the fresh air ratio. The study investigates the flow characteristics of free and confined vortex rings, determines the optimal piston stroke length and radial constraint size, and analyzes the mixing ratios. The inner diameter of the fresh air cavity and the outlet diameter have an impact on the vortex rings.
Article
Mathematics, Applied
Abdelkader Laiadi, Abdelkrim Merzougui
Summary: This study examined free-surface flow past two inclined plates, using numerical methods to solve the problem of incompressible, two-dimensional, steady, and irrotational fluid flow.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Thermodynamics
Shahin Faghiri, Omid Mohammadi, Hossein Hosseininaveh, Mohammad Behshad Shafii
Summary: The study investigated the impact of acetone drops on molten paraffin, categorizing four distinct impact regimes under different Weber numbers and surface temperatures. The research concluded that increased molten paraffin temperature and impact Weber number result in the expansion of solidified paraffin area on the melt free surface.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2021)
Article
Engineering, Electrical & Electronic
Jiwei Li, Yue Hu, Xufan Gan, Feng Gao, Wending Zhang, Ligang Huang, Fang Bo, Guoquan Zhang, Jingjun Xu
Summary: The study presented a tunable bandwidth add-drop filter in the ideal quasicritical coupling state, demonstrating stable efficiency, narrow bandwidth, and a wide tuning range in the experiment. The filter has potential applications in microwave photonics, narrow linewidth lasers, and nonlinear optics.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Thermodynamics
Seyed Moein Rassoulinejad-Mousavi, Firas Al-Hindawi, Tejaswi Soori, Arif Rokoni, Hyunsoo Yoon, Han Hu, Teresa Wu, Ying Sun
Summary: This research explores how deep learning can adapt to new datasets with limited data, studying convolutional neural networks and transfer learning. The study found that transfer learning outperforms convolutional neural networks in cases of data scarcity, demonstrating higher accuracy and lower false negative rates.
APPLIED THERMAL ENGINEERING
(2021)
Article
Mechanics
Rina Nakajima, Kosuke Hayashi
Summary: Experiments were conducted to study the behavior of liquid drops falling through a miscible liquid. It was observed that the drops deform into vortex rings and fragment into smaller drops due to the Rayleigh-Taylor instability. The number of smaller drops was measured for different Archimedes numbers, and the influence of vortex ring interactions on fragmentation was analyzed.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Optics
Kaibo Yang, Hao Luo, Peng Li, Feng Wen, Yuzong Gu, Zhenkun Wu
Summary: In this study, a double-ring vortex beam with adjustable spacing between the two rings was demonstrated, and its size was minimally affected by the change of topological charge. The beam satisfies the concept of a double-ring perfect optical vortex and has potential applications in optical trapping and optical communication.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Chemistry, Physical
Run Liu, Fang-Fang Xie, Ling-Feng Huang, Yi-Feng Wang, Shu-Hang Lv, Han-Wu Liu, Yan-Ru Yang, Xiao-Dong Wang
Summary: Classical molecular dynamics simulations were used to investigate the impact behaviors of water nanodroplets on a hydrophobic surface in the presence of an external perpendicular electric field. The results showed that the maximum spreading factor of the nanodroplets was enhanced by the electric field, especially at higher field strengths. An analytical model was developed to predict the maximum spreading factor for nanodroplets subjected to a perpendicular electric field, showing good agreement with the MD simulations in a low Reynolds number range.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Engineering, Mechanical
Shengchang Tang, Fulei Wang, Zhipeng Qin, Mengchuang Yin, Caijie Li, Yongchao Cai, Xiangfu Wei, Hui You
Summary: This paper experimentally investigates the dynamics of drop formation at low Weber numbers (We = rho(VD)-D-2/sigma). Using a high-speed camera, deionized water drops dripping from nozzles were photographed. The studied drop parameters include the limit length of the filament, the thickness and position of the neck, the size of the drop and satellite droplet, and the movement trend of the satellite droplet. The wettability of the needle nozzle is found to mainly influence the dynamic dripping process by changing the diameter of the contact circle of the three phases.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2023)
Article
Chemistry, Physical
M. Santini, S. Marzorati, S. Fest-Santini, S. Trasatti, P. Cristiani
JOURNAL OF POWER SOURCES
(2017)
Article
Multidisciplinary Sciences
Homa Naseri, Kieran Trickett, Nicholas Mitroglou, Ioannis Karathanassis, Phoevos Koukouvinis, Manolis Gavaises, Robert Barbour, Dale Diamond, Sarah E. Rogers, Maurizio Santini, Jin Wang
SCIENTIFIC REPORTS
(2018)
Article
Chemistry, Physical
S. Marzorati, A. Goglio, S. Fest-Santini, D. Mombelli, F. Villa, P. Cristiani, A. Schievano
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2019)
Article
Computer Science, Interdisciplinary Applications
S. Fest-Santini, J. Steigerwald, M. Santini, G. E. Cossali, B. Weigand
Summary: Numerical simulation accurately reproduces the simultaneous impact of three water drops on a solid wall covered by a thin liquid film, revealing key challenges in numerical modeling of complex phenomena.
COMPUTERS & FLUIDS
(2021)
Article
Energy & Fuels
Pierangela Cristiani, Andrea Goglio, Stefania Marzorati, Stephanie Fest-Santini, Andrea Schievano
FRONTIERS IN ENERGY RESEARCH
(2020)
Review
Engineering, Chemical
Robert Haide, Stephanie Fest-Santini, Maurizio Santini
Summary: X-ray micro-computed tomography is a versatile tool for studying drying processes in porous materials, with an increasing number of publications in the early 2000s indicating ongoing research demand in this field.
Article
Mechanics
Sina Ackermann, Stephanie Fest-Santini, Maziar Veyskarami, Rainer Helmig, Maurizio Santini
Summary: Droplets formed on the hydrophobic surface of a porous medium have a significant impact on the mass, momentum, and energy exchange across the porous interface. The complex fluid displacement front at the pore-scale is influenced by surface wettability and contact angle variation. The droplet formation is affected by pore geometry and surface wettability. This study validates two multi-scale simulations of water droplets emerging from a single hydrophobic capillary pore using high-resolution X-ray imaging. The proposed models provide insight into the droplet formation and its impact on the interface in a coupled free flow-porous medium system.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Physics, Fluids & Plasmas
Manfredo Guilizzoni, Maurizio Santini, Stephanie Fest-Santini
Proceedings Paper
Thermodynamics
M. Santini, M. Guilizzoni, S. Fest-Santini, M. Lorenzi
35TH UIT HEAT TRANSFER CONFERENCE (UIT2017)
(2017)
Article
Mechanics
Phoevos Koukouvinis, Nicholas Mitroglou, Manolis Gavaises, Massimo Lorenzi, Maurizio Santini
JOURNAL OF FLUID MECHANICS
(2017)
Article
Mechanics
Essam Nabil Ahmed, Alessandro Bottaro
Summary: This study focuses on the fully developed, steady, incompressible, laminar flow in a channel with rough and/or permeable walls. The influence of micro-structured boundary surfaces on the flow behavior is simulated using high-order effective boundary conditions derived from homogenization theory without empirical parameters. A closed-form solution of the Navier-Stokes equations is obtained for the flow in the channel, incorporating slip velocities, shear stress, and streamwise pressure gradient at each virtual boundary. The accuracy and applicability of the model are validated against full feature-resolving simulations for different textures. The Stokes-based model used to identify slip and interface permeability coefficients in the effective boundary conditions is reliable and accurate up to a certain threshold, beyond which advective effects need to be considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Mustafa Turkyilmazoglu, Faisal Z. Duraihem
Summary: Thermally-driven natural convection in a porous layer is explored theoretically in this work based on Darcy's law. The study focuses on the non-circulating basic cellular flow between two infinitely long horizontal plates and its instability onset. The results show that a circulatory flow and temperature variation along the horizontal axis govern the motion, and the instability can be determined through linear stability analysis and numerical calculations.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
P. Roca Ramis de Ayreflor, A. Viudez
Summary: In this study, the inelastic interactions between a small, intense dipole and a weak, neutral monopole in two-dimensional flows are examined. It is found that dipoles with small size but large amplitude can cross and scatter off the neutral vortex, while leaving the vortex stable.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Nilanjan Mondal, Chirodeep Bakli
Summary: This study presents a micro-nanochannel junction with directional flow achieved by a combination of junction geometry and wall functionalization. The system acts as a fluid diode with asymmetric pressure drop and flow rate in the nanochannel. The directional junction transport can be tuned with slip length, providing a key parameter for engineering various applications. The findings contribute to the understanding of flow rectification systems in nanochannels and have implications for capillary blood flow, desalination systems, and energy storage devices.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Ussama Ali, Anas Ghannam, Md Islam, Isam Janajreh
Summary: This study utilizes a passive flow control technique involving a slit through a circular structure to dampen flow-induced vibration. The results demonstrate that the presence of a slit can decrease lift and drag coefficients and suppress flow-induced vibration.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sebastian A. Altmeyer
Summary: This article investigates how an alternating magnetic field can restrict and suppress the generation of vortices in ferrofluidic Couette flow. It finds that when the initially rotating outer cylinder is suddenly stopped, more complex vortex dynamics are generated in the system, and the presence of an alternating magnetic field can modify these dynamics, mainly depending on the modulation amplitude of the field.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Pradeep, L. P. Singh
Summary: This study focuses on the analytical solution to the Riemann problem for a 1-D non-ideal flow of dusty gas with external force. The elementary wave curves, including rarefaction wave, shock wave, and contact discontinuity, were obtained and their implications on density, velocity of flow, and shock speed were examined. The addition of external force results in non-self-similar solutions.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Meng Fan, Antoine Dazin, Gerard Bois, Francesco Romano
Summary: This study investigates the prominent features of the primary instabilities of a turbulent source flow between finite-span parallel rings with spatially modulated inflow conditions rotating at angular rate n. Two different two-dimensional instabilities that occur at large and low flow rates have been traced back to two different physical mechanisms related to jet-wake and mean-core flow, respectively. The effect of the radial aspect ratios on the instability characteristics of the flow between parallel rings is also considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Yasmin Hengster, Martin Lellep, Julian Weigel, Matthew Bross, Johannes Bosbach, Daniel Schanz, Andreas Schroder, Florian Huhn, Matteo Novara, Daniel Garaboa Paz, Christian J. Kahler, Moritz Linkmann
Summary: Using curvature and torsion to describe Lagrangian trajectories provides insights into small and large time scales. Probability density functions (PDFs) of curvature and torsion were calculated for experimental Lagrangian trajectories in different flows, and were compared with experimental and numerical simulation results. The effect of anisotropy on geometry or tracer particle trajectories was quantified using the curvature vector, which was found to be related to velocity fluctuations.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Nang X. Ho, Truong V. Vu
Summary: The present paper reports numerical results on the solidification process of a hollow drop on an inclined surface. The drop undergoes deformation and forms an asymmetric tip as the surface angle increases. The solidification time, however, is not affected by the surface angle. The fluid accumulates at the bottom of the drop and the bubble moves upwards before being trapped by solidification. A larger bubble reduces the tip shift. The effect of Bond number and Stefan number on solidification is also considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Idalia Jagodzinska, Bartosz Olszanski, Konrad Gumowski, Slawomir Kubacki
Summary: This study investigates the characteristics of high subsonic and transonic flows through a linear cascade using experimental investigations and numerical simulations. The experiments measured static pressure, flow field, and turbulent intensity, and provided inlet conditions for the numerical simulations. The simulations validated the experimental data and tested the applicability of the turbulence models.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Kun Sung Park, Ali Zamiri, Minsuk Choi, Byung Ju Lee, Jin Taek Chung
Summary: In this study, the stator geometry of a single-stage transonic fan was optimized to improve its aerodynamic performance and stall margin. Steady and unsteady simulations were conducted to analyze the impact of shock waves generated by the rotor blade on the stator inlet flow. Using a design of experiment and response surface method, an optimal geometry of the stator blade was obtained to increase the fan's efficiency and stall margin.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Yuanzhao Zhang, Bo Li
Summary: This study investigated the effects of longitudinal and lateral spacing on the aerodynamic drag characteristics of the whole team and each member in speed skating team pursuit competition. The results showed that decreasing the longitudinal spacing resulted in greater drag reduction for the whole team and individual skaters. Furthermore, lateral movement of the leading skater also led to additional drag reduction for the team. Computational fluid dynamics simulations revealed differences in drag distribution between the leading skater and the middle and last skaters.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sichang Xu, Chris Peirone, Eugene Ryzer, Gary W. Rankin
Summary: This paper presents a study of a special bistable load-type supersonic fluidic oscillator capable of producing self-sustained oscillations in two gas pressure chambers. The experimental portion verifies the robust nature of the device performance and shows distinct differences compared to a similar prototype. A three-dimensional computational fluid dynamics model is required to accurately simulate the transient filling process, leading to an unaffordable computational cost. To address this issue, a low-order fluid circuit model is developed, which provides an accurate and rapid prediction of the transient performance.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sampson Davis, Eli Shellabarger, James Miller, Thomas Ward
Summary: The present work focuses on studying the effects of shock wave - boundary layer interaction in 2D hypersonic flow at the sharp leading edge of a flat plate and a flat plate followed by a compression ramp. A key parameter, the hypersonic interaction parameter x, is defined and analyzed using a semi-analytic reduced-order model. The study aims to improve on existing methods by characterizing the viscous boundary layer and investigating the upstream influence resulting from the compression ramp.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
