Article
Mechanics
Xianrong Liang, Wulei Cai, Honghui Chen, Yunfeng Zhao, Heng Wu, Mengmeng Wang, Gang Jin
Summary: The method proposed in the research generates oscillatory extensional flow using an eccentric cylinder flow, with the frequency and amplitude controlled by the angular velocity and eccentricity of the cylinders. This flow field shows promise as a rheological tool for investigating the effects of extensional flows on dispersion dynamics.
Article
Mechanics
Cuong T. Nguyen, Hung V. Vu, Truong V. Vu, Thuan V. Truong, Nang X. Ho, Binh D. Pham, Hoe D. Nguyen, Vinh T. Nguyen
Summary: This study investigates the dynamical behaviors of compound droplets moving in microchannels, demonstrating that the droplets undergo different deformation or breakup modes under various parameter values, leading to different forms of droplet splitting.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2021)
Article
Mechanics
Dong Wang, Ningning Wang, Haihu Liu
Summary: A three-dimensional lattice Boltzmann method is developed to investigate the deformation and breakup of a Newtonian droplet in the Giesekus fluid matrix under shear flow. The study explores the effects of Deborah number De, mobility parameter alpha, and solvent viscosity ratio beta on droplet deformation, and analyzes the modifications of normal viscous and elastic stresses on the droplet.
JOURNAL OF RHEOLOGY
(2022)
Article
Engineering, Chemical
Jing Zhang, Yibo Gao, Bin Gong, Yaxia Li, Jianhua Wu
Summary: The study investigates the deformation and breakup characteristics of liquid droplets in the concave-wall jet, revealing three different modes of droplet behavior. Droplet breakup mainly occurs in regions with high shear rates.
CHEMICAL ENGINEERING & TECHNOLOGY
(2021)
Article
Mechanics
S. A. Vagner, S. A. Patlazhan
Summary: The deformation and stability of a three-dimensional Newtonian single-core compound droplet during flow in a channel with sudden contraction were investigated using numerical modeling. The study aimed to identify the conditions for the steady transition of a compound droplet into a composite microfiber. The results showed that the effective elongation of the core can be achieved by either increasing the shell viscosity relative to the ambient fluid or decreasing the core viscosity relative to the shell. Additionally, a new mechanism of disintegration of the compound droplet was discovered, caused by the core destabilizing effect resulting from an increase in the relative core/shell interfacial tension or relative core viscosity.
Article
Physics, Multidisciplinary
Sayali N. Jadhav, Uddipta Ghosh
Summary: This study investigates the dynamics and morphology of two-dimensional multicore (dual and triple core) compound drops under oscillating shear flows. The binary-phase-field method is used to obtain numerical solutions for the flow field and droplet deformation characteristics. Results show that the inner cores and the outer drop may exhibit irregular temporal variations in deformation depending on the geometric configuration. Displacement of the center of masses of the drops facilitates irregular deformation, while stationary drops show smooth and periodic temporal variations in shape. The time period of oscillation does not fundamentally alter the morphological characteristics, but impacts the extent of deformation and the phase lag between deformation and flow.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Engineering, Mechanical
Hung V. Vu, Truong V. Vu, Binh D. Pham, Hoe D. Nguyen, Vinh T. Nguyen, Hoa T. Phan, Cuong T. Nguyen
Summary: This study provides a numerical simulation analysis of the dynamics of a compound droplet in circular and sinusoidal-wave tubes. It reveals that the capillary number strongly affects the droplet dynamics and the breakup modes. The droplet deformation increases and it is stretched along the centerline as the Reynolds number increases, while increasing the length of the wavy region enhances the deformation and breakup of the droplet. Regime diagrams based on some of these parameters are plotted as well.
JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY
(2023)
Article
Mechanics
Ali Lafzi, Sadegh Dabiri
Summary: The dynamics of a droplet in oscillatory and pulsating flows of a Newtonian fluid in a microchannel have been studied numerically, exploring the effects of oscillation frequency, surface tension, and channel flow rate. The simulation results are sensitive to grid resolution due to the unsteady behavior of the base flow, and a set of fine grids have been used to capture the physics of the problem accurately. To reduce computational costs, a multifidelity Gaussian processes method with two levels of fidelity has been used to predict results and uncertainties based on correlations with coarse-grid cases.
Article
Thermodynamics
Cosan Daskiran, Xinzhi Xue, Fangda Cui, Joseph Katz, Michel C. Boufadel
Summary: Understanding the shear breakup and droplet formation in jet flows is crucial for determining the final droplet size distribution. Large eddy simulation (LES) was used to study this process, which showed good agreement with experimental results. Different mechanisms of droplet formation were observed, including capillary forces, breakage and attachment of droplets to ligaments, and the influence of viscous and surface tension forces was quantified.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2021)
Article
Chemistry, Physical
Wenchuan Liu, Ning Li, Zhiqian Sun, Zhenbo Wang, Zengli Wang
Summary: This study presents molecular dynamics simulations of droplet collision and coalescence in shear gas flow between gold plates. The results show that parameters such as shear velocity, normal symmetry velocity, and capillary number play a crucial role in determining the behavior of the droplets.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Engineering, Chemical
Guanqiu Wang, Chunying Zhu, Taotao Fu, Youguang Ma
Summary: This study experimentally investigated the deformation of droplets and the formation of tail satellite droplets in microchannels, revealing that the rear cap of the droplet is more prone to deformation. The critical criterion for the formation of tail satellite droplets was proposed, showing good agreement with the experimental results.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Mechanics
Vasco Duke-Walker, Benjamin J. Musick, Jacob A. McFarland
Summary: Shock-driven multiphase mixing is a common phenomenon in various physical systems. In this study, experiments are conducted to investigate simultaneous droplet-scale phenomena under extreme conditions. The results indicate that the breakup of small droplets at high Weber numbers is likely dominated by the Rayleigh-Taylor mechanism.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Mechanics
Xiangdong Liu, Lei Li, Jingwen Yu, Guanqiu Hao, Wei Yu, Yongping Chen
Summary: A 3D mathematical model that couples the phase-field model and the electric current model is used to investigate droplet spheroidizing in an extensional flow field. The study shows that applying an electric field can counteract the hydrodynamic forces on the droplet and lead to spheroidization. The relationship between the critical electric capillary number for droplet spheroidizing and the hydrodynamic capillary number is found to be linear and is influenced by the conductivity and permittivity ratios between the droplet and continuous phase.
Article
Mechanics
K. Mizuno, T. Yada, T. Kamiya, M. Asahara, T. Miyasaka
Summary: The study aims to clarify the deformation behavior of a single droplet in the high Weber number region and show the relationship between fragment spread and initial deformation behavior. The research found no significant relationship between the spread of the fragment and its initial deformation behavior, and identified a relationship between the wavelength of the upstream interface of the droplet and the Weber number.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Engineering, Chemical
Ning Li, Yunhui Pang, Zhiqian Sun, Yongxiang Sun, Zhuang Qi, Wangqing Li, Yue Liu, Bin Li, Zhenbo Wang, Hongbo Zeng
Summary: Polymers have a significant impact on the electrostatic demulsification efficiency of water-in-oil (W/O) emulsions by altering the motion characteristics of water droplets. The addition of polymers increases the polarity of the droplets, promoting their deformation and breakup under an electric field. The migration of polarized polymers and ions ultimately leads to droplet breakup.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
Manash Protim Boruah, Pitambar R. Randive, Sukumar Pati, Kirti Chandra Sahu
Summary: The electrohydrodynamics of a concentric compound drop migrating and deforming in a plane Poiseuille flow under the influence of an arbitrarily orientated uniform electric field is investigated using a double asymptotic approach. The effect of viscosity, conductivity, and permittivity ratios, the orientation of the applied electric field, and radius ratio is thoroughly investigated. The results show that the magnitude of lateral velocity increases with radius ratio, while longitudinal velocity decreases. The influence of the tilt angle of the applied electric field is dampened out when the size of the core increases. The increase in electric Reynolds number enhances the lateral velocity while decreasing the longitudinal velocity, and the lateral and longitudinal velocity of the drop increase with an increase in the capillary number.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Computer Science, Interdisciplinary Applications
Fei Jiang, Haihu Liu, Xian Chen, Takeshi Tsuji
Summary: In this paper, a numerical model for simulating the solid-liquid-gas three-phase flow in unconsolidated particle layers is developed. The model utilizes the discrete element method (DEM) and the lattice Boltzmann method (LBM) to propose a multiphase fluid-solid two-way coupling algorithm. The method is applied to simulate the upward migration of leaked gas bubbles through a brine-filled sediment column at the seafloor and investigate the influences of leak flow rate and interfacial tension on bubble rising behavior. The results indicate three different flow regimes, and the proposed numerical method accurately characterizes various multiphase interaction mechanisms.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
Pavan Kumar Kirar, Surendra Kumar Soni, Pankaj S. Kolhe, Kirti Chandra Sahu
Summary: In this study, the interaction between a droplet and a swirling airstream was experimentally investigated using shadowgraphy and particle image velocimetry techniques. The droplet's morphology and trajectory were found to be influenced by various parameters in the swirl flow, resulting in different breakup modes. Compared to straight flow, swirl flow promoted the stretching of the droplet's surface and led to a new breakup phenomenon.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Chemistry, Multidisciplinary
Pallavi Katre, Saravanan Balusamy, Sayak Banerjee, Kirti Chandra Sahu
Summary: We experimentally studied the evaporation behavior of water-ethanol binary droplets loaded with alumina nanoparticles on a critically inclined heated surface and compared it with the no-loading condition. We found that the critical angle for droplet sliding increases with ethanol-rich binary droplets and that the pinning effect caused by nanoparticles results in larger perimeter and surface area for the droplets, enhancing the evaporation rates and decreasing their lifetime significantly. Additionally, increasing ethanol concentration leads to complex thermosolutal Marangoni convection.
Article
Thermodynamics
Pradeep Gurrala, Saravanan Balusamy, Sayak Banerjee, Kirti Chandra Sahu
Summary: This study investigates the evaporation of pure ethanol, water, and ethanol-water binary droplets on one-dimensional cylindrical substrates using shadowgraphy and infrared imaging techniques. The results reveal different wetting behaviors of droplets on curved and flat substrates, and the three-dimensional solid modeling provides insights into the morphological evolution during evaporation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Anant Kumar Nema, Manoj Kumar Tripathi, Kirti Chandra Sahu
Summary: In this study, we numerically investigate the deformation and migration of a viscoelastic droplet in a ratchet microchannel. We discover that the presence of the ratchet section significantly influences the shape and dynamics of the droplet.
JOURNAL OF NON-NEWTONIAN 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
Thermodynamics
Jiankun Zhang, Haihu Liu
Summary: The erosion caused by solid particles poses a significant threat to the safety and reliability of turbines. This study numerically investigates the impact of particle size, blade tip clearance, rotation speed, and off-design condition on erosion and performance using the Oka erosion model. The results show that particle injection leads to decreased efficiency, with high erosion occurring near the trailing edge at the pressure side and the leading edge at the suction side. The erosion can be alleviated by larger tip clearances and lower rotation speeds, while the off-design condition significantly reduces efficiency and increases erosion.
Article
Engineering, Chemical
Pallavi Katre, Sayak Banerjee, Saravanan Balusamy, Kirti Chandra Sahu
Summary: We investigated the retention force factor of pure and binary droplets laden with alumina nanoparticles placed on an inclined substrate. The critical angle of ethanol droplet increased with nanoparticles concentration, while for water-ethanol droplets, it reached a plateau and slightly decreased after 0.6 wt% nanoparticle loading. We proposed correlations for the retention force factor and critical angle and found that evaporating droplets with nanoparticle loading exhibited richer hydrothermal waves. This study is the first attempt to investigate the retention force factor for droplets loaded with nanoparticles on an inclined substrate.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Mechanics
Someshwar Sanjay Ade, Lakshmana Dora Chandrala, Kirti Chandra Sahu
Summary: The size distribution of child droplets resulting from dual-bag fragmentation of a water drop is studied using shadowgraphy and digital in-line holography techniques. The fragmentation of the parent drop contributes to small droplet atomization, while core drop disintegration leads to larger fragments. The dual-bag fragmentation exhibits a bi-modal size distribution, while the single-bag breakup shows a tri-modal size distribution. An analytical model developed by Jackiw & Ashgriz accurately predicts the experimentally observed droplet volume probability density for dual-bag fragmentation.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
P. A. L. Ankush, P. A. L. Narayana, Kirti Chandra Sahu
Summary: The study investigates the instability characteristics of double-diffusive mixed convective flow with viscosity stratification in a vertical channel. The viscosity of the fluid is modeled as an exponential function of temperature and concentration, with an activation energy parameter determining its sensitivity. Three scenarios are considered: thermal diffusion only, temperature and solute acting in the same direction, and temperature and solute acting in opposite directions. The results show that higher activation energy parameters lead to increased flow stability.
Article
Mechanics
Ronghong Zhou, Sheng Li, Liang Shi, Ningning Wang, Yong Liu, Haihu Liu
Summary: In this study, a theoretical and numerical investigation is carried out on the flow of a compound droplet through a single pore-throat structure. A theoretical model is developed to predict whether the compound droplet can penetrate the throat by quantifying the capillary pressures in the pore and throat under different geometrical conditions. Lattice Boltzmann simulations are also conducted to validate the theoretical model and explore the influence of various factors on the invasion behavior of the compound droplet.
Review
Mechanics
Ranajit Mondal, Hisay Lama, Kirti Chandra Sahu
Summary: Drying complex fluids involves physical processes such as diffusion of liquid molecules and evaporation-driven flow, resulting in unique patterns and structural defects in the dried deposit. This review focuses on drying colloids, particularly the drying-induced effects observed during sessile drop drying. Theoretical overviews of drying pure and binary liquid droplets, as well as colloidal droplets, are presented, along with explanations of pattern formation and desiccation cracks. The impact of evaporation-driven flows on particle accumulation and physical parameters influencing deposit patterns and cracks are briefly described.
Article
Multidisciplinary Sciences
Surya Narayan Maharana, Kirti Chandra Sahu, Manoranjan Mishra
Summary: This study analyzes the linear stability of a reactive plane Poiseuille flow in a two-dimensional channel where two miscible reactants A and B produce a viscous product C. The effects of various parameters such as mobility ratio, Damkohler number, Schmidt number, Reynolds number, and reactive zone characteristics on stability are examined. It is found that even a small viscosity stratification due to reaction can destabilize the flow at moderate and low Reynolds numbers, and the instability occurs due to the overlap of the critical layer with the viscosity-stratified layer. Surprisingly, in some cases, the reaction leads to a decrease in σM with increasing Reynolds number.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Engineering, Multidisciplinary
Muhammad Sami Rashad, Haihu Liu, Shan Ali Khan
Summary: In this study, a mathematical modeling approach was used to investigate the unsteady stagnation point flow of Oldroyd-B nanofluid, taking into account the thermal conductivity and solutal diffusivity with bioconvection mechanism. The effects of Joule heating, Arrhenius activation energy, and convective boundary conditions were considered. The results showed that increasing the buoyancy ratio parameter reduces fluid velocity, while increasing the mixed convective parameter enhances fluid flow. The temperature profile is influenced by nonlinear thermal radiation and temperature dependent thermal conductivity. The concentration profiles of nanoparticles exhibit opposite behaviors for the Brownian motion coefficient and thermophoresis diffusion parameter. By varying the Peclet number, the microorganisms profile is observed to decrease. The findings of this study are significant for controlling and optimizing heat transfer in industrial applications.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2022)
Article
Mechanics
Nicolas Bouvet, Savannah S. Wessies, Eric D. Link, Stephen A. Fink
Summary: This study presents a framework to characterize firebrand flows and compare exposure through the use of a measurement device and data processing methods. The ability to perform exposure comparisons and recognize combustion states is demonstrated.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
P. Botticini, G. Lavalle, D. Picchi, P. Poesio
Summary: This study investigates the gravity-driven liquid layer problem on an inclined plate, taking into account the variable density of the fluid. The study examines the influence of density variation on the formulation of a depth-averaged model and the role of compressibility in long-wave interfacial instability.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Jean-Paul Caltagirone
Summary: This article introduces a method for modeling capillary flows on a surface or at the interface of two fluids. The method involves handling the two components of capillary acceleration using the divergence and curl of surface normal. The proposed formulation is characterized by directional curvature based on dihedral angle, intrinsic anisotropic surface tension per unit mass, and introduction of capillary potential.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Qi-Teng Zheng, Chun-Bai-Xue Yang, Shi-Jin Feng, Yu-Chen Song, Yong Zhao, Yu-Lin Wu
Summary: This paper proposes a new two-phase partitioning boundary model to accurately predict the drying process of a porous medium from saturated to unsaturated conditions. The model is validated through laboratory soil drying tests and the study also investigates the effects of air-water interfacial area and water retention parameters on the drying process.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Alexandra Metallinou Log, Morten Hammer, Svend Tollak Munkejord
Summary: Flashing flow is commonly found in industrial systems and accurate flashing models are essential for the design of safe and efficient CO2 transportation systems. We propose a homogeneous flashing model that takes into account the physical phenomena of phase change. The model is fitted using CO2 pipe depressurization data and we find that the same model parameters can be applied for different cases.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Q. Tan, S. A. Hosseini, A. Seidel-Morgenstern, D. Thevenin, H. Lorenz
Summary: The possible impact of temperature differences during crystal growth is investigated in this study. A numerical model is developed to simulate the crystallization dynamics of (S)-mandelic acid, taking into account temperature effects. The study shows that the heat generation at the crystal interface has only a small effect on the surrounding temperature field.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Hideki Murakawa, Sana Maeda, Sven Eckert
Summary: This study investigates the behavior of bubbles in a liquid metal under the influence of a magnetic field, particularly bubble chains. The results show that increasing the magnetic field strength suppresses the oscillations of the bubbles and concentrates their crossing positions in a specific area. Applying these findings to numerical models can further optimize continuous casting processes.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Johanna Potyka, Kathrin Schulte
Summary: This paper presents an advanced Volume of Fluid (VOF) method for performing three-dimensional Direct Numerical Simulations (DNS) of the interaction of two immiscible fluids in a gaseous environment with large topology changes. The method includes efficient reconstruction of phase boundaries near the triple line using a Piecewise Linear Interface Calculation (PLIC) method and enhanced surface force modeling with the Continuous Surface Stress (CSS) model. Implementation of these methods in the multi-phase flow solver Free Surface 3D (FS3D) yielded successful validation. The simulations provide valuable insights into the collision process and can support future modeling of immiscible liquid interaction.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Martin Rohde, Sebastian Burgmann, Uwe Janoske
Summary: This study investigates the effect of superimposing an incident flow and two-dimensional vibration on the critical air flow velocity required for the detachment of a droplet. The results show that oscillatory excitation at specific frequencies can significantly reduce the critical velocity for droplet detachment.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Tea-Woo Kim, Baehyun Min
Summary: Liquid-gas two-phase slug flow is a complex flow pattern in energy systems, and accurately predicting slug liquid holdup is crucial for system design and operation. Existing HLLS models have limited applicability due to a lack of physical basis. This study proposes a new dimensionless number SP and correlates it with HLLS data, resulting in a unified HLLS correlation that agrees closely with experimental data.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Christian Lieber, Stephan Autenrieth, Kai-Yannic Schoenewolf, Amy Lebanoff, Rainer Koch, Sterling Smith, Paul Schlinger, Hans-Joerg Bauer
Summary: The observation of acoustically levitated droplets offers great potential for studying their evaporation characteristics. The main objective of this study is to present an experimental setup that minimizes the disturbing effects of the levitation technique in order to investigate convective heat and mass transfer during droplet evaporation.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Facundo Cabrera-Booman, Nicolas Plihon, Mickael Bourgoin
Summary: The settling behavior of individual spheres in a quiescent fluid was experimentally studied. The mean trajectory angle with the vertical showed complex behavior as the parameters Gamma and Ga varied. The transition from planar to non-planar trajectories and the emergence of semi-helical trajectories were observed, especially for denser spheres.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Hongbin Wang, Hanwen Luo, Jinbiao Xiong
Summary: This article introduces an iterative screening method for closure models in nucleate boiling flow simulation, and demonstrates its accuracy through experiments.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Alexandra Metallinou Log, Morten Hammer, Han Deng, Anders Austegard, Armin Hafner, Svend Tollak Munkejord
Summary: This study investigates the rapid depressurization of liquid CO2 and compares the predictions of different models. It is found that higher temperatures result in shorter relaxation times.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)
Article
Mechanics
Rizwan Zahoor, Sasa Bajt, Bozidar Sarler
Summary: This numerical study evaluates the jet characteristics of non-Newtonian power-law fluids in a gas dynamic virtual nozzle. The results show that shear-thinning fluids result in thicker, longer, and slower jets compared to shear-thickening fluids. Additionally, a dripping-jetting phase diagram of the nozzle is obtained by varying the power law index, gas, and liquid flow rates.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2024)