Article
Mechanics
Priya Verma, Vandita Sharma, Manoranjan Mishra
Summary: This study provides numerical insights into the radial displacement of two viscously stable reactants undergoing an infinitely fast chemical reaction, expanding the numerical knowledge of the interaction between chemical reaction and hydrodynamic instability. By calculating the onset time of instability and dividing the time domain into stable and unstable zones, the characteristics of reactants in terms of flow stability can be characterized. The dependence of the onset time of instability on the mobility ratio and the Peclet number is obtained, and the length of the fingers in the unstable zone is found to be dependent on the sign of the mobility ratio.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Shoji Seya, Ryuta X. Suzuki, Yuichiro Nagatsu, Takahiko Ban, Manoranjan Mishra
Summary: We developed coupled evolution equations for viscous fingering and phase separation, and demonstrated the transition of VF pattern into droplet formation pattern by spinodal decomposition effect. The experimental results matched the theoretical predictions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Vandita Sharma, Hamirul Bin Othman, Yuichiro Nagatsu, Manoranjan Mishra
Summary: Through numerical computations and experimental studies, miscible viscous fingering (VF) in an annulus is examined, showing contrast to classical radial VF and instability of a straight displaced slice. The persistence of VF in a miscible annular ring is observed, with variance as a non-monotonic function indicating interaction of two fronts, pressure fingers growing faster than concentration fingers. The variation of finger length with flow rate depends on the amount of more viscous fluid in the annulus, with critical parameters for instability related to viscosity contrast and sample amount.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Min Chan Kim, Lopamudra Palodhi, Joung Sook Hong, Manoranjan Mishra
Summary: The coupled effects of thermodynamic and hydrodynamic instabilities during viscous fingering (VF) are studied using a modified Cahn-Hilliard phase-field model. The temporal evolution of spatial inhomogeneities is investigated by describing the free energy using a modified Flory-Huggins model. The governing equations are solved using COMSOL multiphysics software, and the results are in agreement with experimental and numerical results obtained using classical models. The effects of the Margules parameter and gradient parameter on VF are systematically studied, showing asymmetric features and a stronger thermodynamic effect with increasing phase separation and droplet formation.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
D. A. Bratsun, A. Mizev, E. A. Mosheva
Summary: Theoretical study of buoyancy-driven chemoconvection induced by a neutralization reaction in a system of nitric acid and sodium hydroxide solutions reveals richer possible instabilities than previously thought. The formation of patterns depends on a single parameter, the reaction-induced buoyancy number, leading to insights necessary for a full understanding of the observed phenomena. The mathematical model developed includes reaction-diffusion-advection equations coupled with Navier-Stokes equations, with a focus on transient linear stability analysis and numerical simulations to examine system dynamics.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mathematics, Applied
Amlan K. Barua
Summary: This article presents a spectrally accurate boundary integral method to investigate the evolution of a Hele Shaw blob in a rotating, radial cell with time dependent gap. The method of complex moments is used to characterize the solution of the moving boundary problem and linear analysis is conducted to investigate the morphology. The results suggest a destabilizing influence of rotation. Numerical simulations using a boundary integral technique reveal that rotation causes a more complex pattern on the fluid interface, with the formation of narrow fingers and more splitting. A method for controlling viscous fingering is also proposed and validated through simulations.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2022)
Article
Chemistry, Physical
Dongqi Li, Zhibing Yang, Renjun Zhang, Ran Hu, Yi-Feng Chen
Summary: The presence of particles in multiphase flow can alter interfacial dynamics and induce various morphological patterns, while particle aggregations significantly enhance interface instability. Experimental findings demonstrate that particle-induced perturbations lead to earlier fingering and more fingers, with an in-depth explanation of the particle deposition mechanism.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Gongtian Gu, Jin Huang, Wenhu Han, Cheng Wang
Summary: Experimental investigation was conducted on flame propagation in Hele-Shaw cells with a micro-sized gap. Different regimes of flame propagation were identified based on gap size, leading to various flame front morphologies and speeds. The non-accelerating flame in narrow gaps exhibited distinct behaviors compared to the self-accelerating flame in wider gaps, influenced by hydrodynamic instabilities.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Mechanics
Patrick K. Mortimer, Andrew W. Woods
Summary: This study examines the release of preferentially wetting fluid in a V-shaped channel, investigating initial exchange flow and later spreading of the wetting fluid along the narrow part of the channel. The behavior of the fluid is influenced by buoyancy and capillarity under different conditions.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Sourojeet Chakraborty, Arun Ramachandran
Summary: A depth-averaged, convection-dispersion equation is derived for the particle volume fraction distribution in the pressure-driven flow of a concentrated suspension of neutrally buoyant, non-colloidal particles. The Taylor-dispersion coefficient scales with characteristic velocity, channel depth and particle radius. Shear-induced migration causes particle redistribution perpendicular to flow. The linear stability analysis shows growth rate and wavenumber scaling with velocity and particle size in the flow direction.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Yuka F. Deki, Yuichiro Nagatsu, Manoranjan Mishra, Ryuta X. Suzuki
Summary: Viscous fingering or Saffman-Taylor instability occurs when a more mobile fluid displaces a less mobile one in porous media, creating finger-like patterns. The effective interfacial tension (EIT) acts like capillary force at the miscible interface. Numerical studies have shown that fingers are wider with EIT. However, a recent experiment on a miscible system with EIT observed finger widening with increasing flow rate, which is not observed in other systems. This study numerically investigates the effect of injection flow rates on miscible viscous fingering with and without EIT, and explains the mechanism using a one-dimensional analysis of concentration and EIT profiles.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Chemical
Daniel Keable, Alistair Jones, Samuel Krevor, Ann Muggeridge, Samuel J. Jackson
Summary: This study presents the results of displacement experiments in a Hele-Shaw cell, which show the complexity of fingering patterns increases with viscosity ratio and Peclet number, and the onset of fingering is delayed compared to linear displacements. Numerical simulations provide good predictions of breakthrough times and sweep efficiency at intermediate Peclet numbers, but fail to replicate fine-scale and macroscopic measures. We suggest exploring 3D models with varying dispersion formulations to capture a wider range of effects at high viscosity ratio and Peclet number.
TRANSPORT IN POROUS MEDIA
(2022)
Article
Mechanics
Sebastian Dehe, Imke-Sophie Rehm, Steffen Hardt
Summary: A two-dimensional dispersion model for a dissolved species in non-uniform flow fields inside a Hele-Shaw cell is derived, incorporating an effective dispersion tensor field and advection-correction terms. The model is validated by comparing results with three-dimensional Lagrangian particle tracing simulations, showing good agreement for various test cases.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Zhiying Hai, Prabir Daripa
Summary: We theoretically study the linear stability of the Saffman-Taylor problem and find that the viscosity ratio eta(r)/eta(l) plays a decisive role in determining stability.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Mechanics
Oleg A. Logvinov
Summary: The renowned problem of viscous fluid displacement by a less viscous one in a Hele-Shaw cell is considered in this study. Both fluids exhibit non-Newtonian properties with power-law viscosity dependence. A unified approach is used to derive averaged two-dimensional equations of motion, and linear stability analysis of the radial interface is conducted with a new key idea of characteristic size selection even without stabilizing factors.
Article
Materials Science, Paper & Wood
Aref Abbasi Moud, Milad Kamkar, Amir Sanati-Nezhad, Seyed Hossein Hejazi, Uttandaraman Sundararaj
Article
Chemistry, Physical
Parisa Bazazi, S. Hossein Hejazi
Summary: The study hypothesizes that the synergy between nanoparticles in one phase and micelles in the other phase can spontaneously generate double emulsions. Experimental results indicate that the gradual surface activation of nanoparticles is crucial in self-double emulsification and controlling the emulsion intensity. Incorporating nanoparticles into spontaneous emulsification systems offers new avenues for designing emulsion-based materials.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Aref Abbasi Moud, Milad Kamkar, Amir Sanati-Nezhad, Seyed Hossein Hejazi, Uttandaraman Sundararaj
Summary: This report investigates the viscoelastic and mechanical behavior of hybrid PVA-CNC hydrogels aggregated with NaCl salt, revealing wide distribution of pores with similar average sizes in almost all samples. The sudden jump in storage modulus at CNC loadings near the percolation threshold suggests the formation of a 3D network, while a more dramatic jump at higher CNC concentrations indicates the establishment of a secondary network structure. The study demonstrates successful fabrication of a healable hydrogel and explores interactions between CNC-CNC and PVA-CNC, offering possibilities for developing advanced materials for tissue engineering and regenerative medicine applications.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Energy & Fuels
Zheyu Liu, Maojie Chai, Xin Chen, Seyed Hossein Hejazi, Yiqiang Li
Summary: Experimental investigation of flow regimes in a rectangular micmchannel using a water-oil system revealed four distinct flow regimes based on parameters such as viscosity ratios, velocity ratios, and capillary numbers. An exponential correlation was found between viscosity ratio and velocity ratio in transitioning flow regimes, with different effects on droplet size and slug length.
Article
Chemistry, Multidisciplinary
Shruti Mendiratta, Ahmed Atef Ahmed Ali, Seyed Hossein Hejazi, Ian Gates
Summary: This study reported the synthesis of novel smart HaP magnetic nanoparticles and their corresponding stimuli-responsive Pickering emulsions, as well as their behavior under confined spaces using a microfluidic platform. The pH-responsive Pickering emulsions prepared with magnetic stearic acid-functionalized nanoparticles showed promising applications in pharmaceutical and petroleum industries. The emulsification-demulsification cycling and response to a magnetic field demonstrated the potential of these smart nanoparticles for controlled emulsions in various industries.
Article
Engineering, Chemical
Hossein Khorshidian, Saied Afshari, Hadi Bagherzadeh, Seyed Hossein Hejazi
Summary: In heterogeneous porous media, the stability of the waterfront is controlled by capillary and viscous forces in the absence of gravity effects. A flow-swing mechanism introduced during water flooding in an oil-wet medium can improve waterflood efficiency and enhance oil sweep efficiency by attenuating advanced fingers and decreasing waterfront instabilities.
TRANSPORT IN POROUS MEDIA
(2021)
Article
Engineering, Chemical
Parisa Bazazi, S. Hossein Hejazi
Summary: The study investigates the influence of cellulose nanocrystals on oil-water interfacial viscoelasticity, demonstrating that the nanocrystals can enhance emulsification stability and create stable emulsions. Additionally, the nanocrystals aid in preventing drop coalescence and prolonging the duration of the early-time spreading regime in emulsification experiments.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Multidisciplinary Sciences
Emad A. Mohammed, Mohammad Keyhani, Amir Sanati-Nezhad, S. Hossein Hejazi, Behrouz H. Far
Summary: This work develops a robust classifier for a COVID-19 pre-screening model by processing variable numbers of cough sound recordings and overcoming the challenge of low COVID-19 positive cases in the data.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Paper & Wood
Aref Abbasi Moud, Amir Sanati-Nezhad, Seyed Hossein Hejazi
Summary: This study evaluates the stability and self-healing ability of cellulose nanocrystal hydrogels using quantitative fluorescence signal analysis. Hydrogel samples with lower cellulose nanocrystal concentrations collapse more rapidly under gravity, while increasing concentration inhibits particle mobility and hinders the self-healing process.
Article
Chemistry, Multidisciplinary
Milad Kamkar, Elnaz Erfanian, Parisa Bazazi, Ahmadreza Ghaffarkhah, Farbod Sharif, Ganhua Xie, Aadithya Kannan, Mohammad Arjmand, S. Hossein Hejazi, Thomas P. Russell, Gerald G. Fuller, Uttandaraman Sundararaj
Summary: The assembly of graphene oxide (GO) at oil/water or air/water interfaces significantly increases the elasticity of the interface, making it an exceptional candidate for stabilizing the O/W interface. This super elastic character is utilized for all-liquid 2D printing, highlighting the potential applications in electronics, fluidic devices, and controlled release systems.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Parisa Bazazi, Seyed Hossein Hejazi
Summary: Controlled transport of liquid droplets on solid surfaces is critical in various practical applications. In this study, non-contact aqueous drops are created on hydrophilic surfaces in an oleic environment and used to deposit submicrometer droplets encapsulating nanoparticles onto solid surfaces. The effect of surfactant and nanoparticle concentrations on wetting dynamics is studied, and a range of droplet spreading regimes is identified. This methodology enables the patterning of droplets in numerous applications, from pharmaceutical carriers to cosmetics and biomedical diagnoses.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Materials Science, Paper & Wood
Aref Abbasi Moud, Milad Kamkar, Amir Sanati-Nezhad, Seyed Hossein Hejazi
Summary: This article reviews the microstructural characterization of cellulose nanocrystal (CNC)-based suspensions and hydrogels using imaging and rheological approaches, and introduces new applications of CNC suspensions and gels. Fine-tuning the properties of CNC colloids using existing methods and models is crucial due to the significant potential of CNC-based products in various fields.
Article
Multidisciplinary Sciences
Hossein Zargartalebi, S. Hossein Hejazi, Amir Sanati-Nezhad
Summary: The authors introduce a passive protocol to suppress the coffee-ring effect and form uniform films at micro- and nanoscales by combining superhydrophilic substrate with a neutral-wetting low-roughness mold. This method has broad applications in fabricating ordered coatings, producing nanofilters, and creating functionalized nanosensors.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Parisa Bazazi, Howard A. Stone, S. Hossein Hejazi
Summary: All-in-liquid printing enables the printing of functional networks in liquid medium, providing vast applications in fields such as functional cell engineering.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Parisa Bazazi, Howard A. Stone, S. Hossein Hejazi
Summary: This study experimentally investigates the break-up of a liquid filament with silica nanoparticles in a surfactant-containing oil phase. It is found that when a viscoelastic layer forms at the interface, the pinch-off dynamics follows exponential decay. A simple approach is introduced to estimate the viscoelastic properties of liquid-fluid interfaces and the thickness of the interfacial layer, where direct measurement of interfacial rheology is not possible.
PHYSICAL REVIEW LETTERS
(2023)