Article
Mechanics
David Barreiro-Villaverde, Anne Gosset, Marcos Lema, Miguel Alfonso Mendez
Summary: In this article, the stability of a thin liquid film dragged by a vertical substrate moving against gravity is investigated in the context of coating processes. The receptivity of the film to three-dimensional disturbances is discussed using Direct Numerical Simulations, an in-house non-linear Integral Boundary Layer film model, and Linear Stability Analysis. The results show that transverse modulations can be beneficial for damping two-dimensional waves in air-knife and slot-die coating processes.
Article
Optics
A. N. Darinskii
Summary: Theoretical study on the existence of nonradiative surface plasmon polaritons (SPPs) in an isotropic metal film surrounded by optically anisotropic half-infinite dielectrics establishes the maximum number of SPPs at a given value of the tangential wave number. The analysis shows that the number of SPPs is limited by the properties of the dielectric medium, with different scenarios yielding varying numbers of SPPs. The insertion of a metal film into an infinite bianisotropic and/or magneto-optically active medium can also guide a maximum of three SPPs.
Article
Engineering, Environmental
Boxiao Li, Jun Li, Dongkai Ni, Songsong Tang, Juncheng Fan, Kaiyuan Shi, Zhen Li, Jian Zhou
Summary: Using a liquid substrate for thin-film processing provides advantages in controlling the system conditions and achieving high-performance films. We developed a liquid-substrate-based spontaneous spreading technology that allows for the formation of polymer thin films on liquid substrates with nanometer to micrometer thicknesses, providing a simple route to control the geometry.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Ivan S. Maksymov, Andrey Pototsky
Summary: Solitary-like surface waves originating from falling liquid films on an inclined plane under low-frequency vibration have unique properties and are of interest in theoretical and experimental research. We investigated the dynamics of these waves and found that the vibration decreased their average and peak amplitudes, but had little effect on their propagation speed. This makes them suitable for practical applications where pulses carrying information need to be immune to external vibrations.
APPLIED SCIENCES-BASEL
(2023)
Article
Acoustics
Erlend Magnus Viggen, Havard Kjellmo Arnestad
Summary: This article investigates an enhanced model for sound radiation near and below coincidence. Unlike the classical model, this model fully respects conservation of energy by balancing the radiated power with power lost from the guided wave underlying the vibration. The model successfully validates against exact solutions for leaky A0 Lamb waves around coincidence.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Biochemistry & Molecular Biology
Ziran Ye, Haixia Huang, Fengyun Xu, Ping Lu, Yiben Chen, Jiawei Shen, Gaoxiang Ye, Fan Gao, Bo Yan
Summary: We prepared metal films of different thicknesses on liquid substrates using thermal evaporation and studied the effect of annealing on these films. Gold films deposited on a silicone oil surface consisted of numerous branched aggregates containing abundant gold nanoparticles. Thermal annealing caused the reintegration of nanoparticles, resulting in significant changes in the surface morphology and microstructure of the gold films. The dependence of the annealing conditions on the surface-enhanced Raman scattering performance of gold films was investigated, and the experimental results were verified by simulation analysis. The study on the optimal annealing temperature of surface-enhanced Raman scattering substrate will facilitate the potential application of films deposited on liquid surfaces in microfluidics and enhanced Raman detection.
Article
Mechanics
D. V. Lyubimov, T. P. Lyubimova, A. A. Cherepanov
Summary: The paper discusses the resonance oscillations of a drop surrounded by a fluid of different density in zero gravity conditions under small amplitude vibrations. When viscosity is small, the resonance oscillations of the drop can be calculated using linear approximation, but finite viscosity has a destabilizing effect on resonance.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Souradip Chattopadhyay, Akshay S. Desai, Amar K. Gaonkar, Anandamoy Mukhopadhyay
Summary: We investigate the behavior of a thin liquid film flowing over a thin compliant substrate. Breaking the time-reversal symmetry introduces significant effects of the odd component of the Cauchy stress tensor, which have not been explored before. By employing the long-wave theory, we derive equations that couple the film's thickness and the compliant substrate, including considerations of inertia, damping effects, wall tension, and odd viscosity. Our linear stability analysis reveals that the compliant substrate destabilizes the system, while the odd viscosity significantly stabilizes it. Additionally, we employ a weakly nonlinear approach and derive the Kuramoto-Sivashinsky equation from the coupled long-wave equations. Remarkably, incorporating the odd viscosity tensor component can prevent chaotic behavior in compliant substrates under the weakly nonlinear limit. Numerical simulations demonstrate remarkable effects of odd viscosity on substrate deflection, and our numerical investigation of the coupled long-wave equations confirms the consistency of the linear and weakly nonlinear theories with the numerical results.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Nanoscience & Nanotechnology
Ines Gharbi, Viviana Palacio-Betancur, Habib Ayeb, Dominique Demaille, Juan J. de Pablo, Randall D. Kamien, Emmanuelle Lacaze
Summary: The impact of organized gold nanoparticles on liquid crystal films was studied, showing that the properties of the liquid crystal films and the distribution of gold nanoparticles can influence each other.
ACS APPLIED NANO MATERIALS
(2021)
Article
Mechanics
Misa Ishimura, Sophie Mergui, Christian Ruyer-Quil, Georg F. Dietze
Summary: This study investigates the effects of a confined turbulent counter-current gas flow on the waviness of a weakly inclined falling liquid film. Experimental and computational methods are used to analyze the linear and nonlinear wave dynamics. The study finds that the gas pressure gradient plays a significant role in countering the stabilizing effect of the tangential gas shear stress. The results also show that the counter-current gas flow can both suppress and amplify the instability of the liquid film, depending on the inclination angle.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Sophie Mergui, Gianluca Lavalle, Yiqin Li, Nicolas Grenier, Georg F. Dietze
Summary: Experiments were conducted in a weakly inclined rectangular channel with a laminar counter-current air flow to investigate the effect of the air flow on the height, shape, and speed of two-dimensional traveling nonlinear waves. The results show a significant difference compared to previous experiments in a weakly confined channel, where the air flow was destabilizing. In the strongly confined configuration, the air flow has a stabilizing effect and can attenuate the waves.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Electrical & Electronic
Xiguang Feng, YoungHoon Kim, Kyoung-Su Park
Summary: A dynamic model was established to analyze the behavior of a vibration droplet on a substrate, including changes in contact angle and contact line. Equations were derived to describe the spreading velocity and final equilibrium angle of the droplet, offering new ways to depict the droplet spreading motion. The study also discussed the re-equilibrium state of the droplet during the vibration process and analyzed the impact of changing contact angles on droplet dynamics under vertical vibration conditions.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2023)
Article
Multidisciplinary Sciences
Anatoliy Vorobev, Sergei Prokopev, Tatyana Lyubimova
Summary: Mechanical vibrations can affect the distribution of fluids in porous matrices by altering their static and dynamic states. A theory based on the elasticity of solid matrices and compressibility of fluids explains the non-destructive changes induced by vibrations. However, field trials have shown that the effects of vibrations in geological reservoirs can occur on a larger scale than expected. This study focuses on the time-averaged effects induced by small-amplitude high-frequency vibrations and examines the displacement flows of immiscible liquids in capillaries under translational vibrations. The research finds that vibrations can change the shapes of menisci and alter the rates of displacement flows, contrary to the common expectation that vibrations facilitate fluid release from porous matrices.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Mechanics
Tsvetelina Ivanova, Fabio Pino, Benoit Scheid, Miguel A. Mendez
Summary: This study extends the classic three-dimensional integral boundary layer (IBL) model to consider the stability of liquid films on moving substrates. Through linear and nonlinear analysis, it is found that coating processes such as hot-dip galvanization and vertical slot-die coating are stable under various flow conditions.
Article
Chemistry, Physical
Palash Dhara, Rabibrata Mukherjee
Summary: This paper reports on the morphology, phase separation, instability, and dewetting of Polymer dispersed liquid crystal (PDLC) thin film comprising nematic liquid crystal, 4-n-pentyl-4'-cyanobiphenyl (5CB), and Polystyrene (PS). It is found that the thickness and composition of the film play a crucial role in their properties, and topographically patterned substrates can help align the phase-separated LC domains.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Mechanics
E. S. Benilov
JOURNAL OF FLUID MECHANICS
(2019)
Article
Physics, Fluids & Plasmas
E. S. Benilov
PHYSICAL REVIEW FLUIDS
(2020)
Article
Mechanics
E. S. Benilov
Summary: This paper analyzes the flow characteristics of steady liquid curtains and discovers multiple stable solutions under certain conditions, depicting a rich variety of behaviors.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
A. Dubovskaya, E. S. Benilov
Summary: The study shows that when the swirling velocity exceeds a certain threshold, the jet will bend against gravity and rise; the contributions of the swirl and streamwise velocities to the centrifugal force in opposite directions can cause the jet to bend in different directions, and viscosity-dominant jets can reach farther distances in some cases.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
E. S. Benilov
Summary: This paper presents an additional mechanism for the evaporation of liquid drops and investigates the influences of disparities between the drop and vapor on the evaporation process. Experimental results demonstrate that the direction of evaporation is determined by vapor density and drop size, and a critical radius exists in oversaturated vapor, with smaller drops evaporating and larger drops acting as centers of condensation and growth.
Article
Mechanics
E. S. Benilov
Summary: The dynamics of saturated vapor between two intersecting walls is examined, showing that small angles between the walls lead to the instability of the vapor and spontaneous condensation in the corner, resulting in the formation of a growing liquid meniscus.
Article
Mechanics
E. S. Benilov
Summary: The fundamental properties of the multicomponent diffuse-interface model (DIM), such as the maximum entropy principle and conservation laws, are utilized to investigate basic interfacial dynamics and phase transitions in fluids. Stable flat interfaces with monotonically changing densities of components are demonstrated. The behavior of a liquid layer in contact with oversaturated but stable vapor is found to either fully evaporate or perpetually expand, depending on the initial disturbance, while a liquid in contact with saturated vapor always evaporates. Spontaneous condensation occurs in vapor bounded by a solid wall with a large enough contact angle. The external parameters of the multicomponent DIM, specifically the Korteweg matrix describing long-range intermolecular forces, are determined for the water/air combination. The Soret and Dufour effects are shown to be negligible in this case, and the interfacial flow is close to isothermal.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
E. S. Benilov
Summary: This article examines non-vertical liquid curtains with large Froude numbers. The structure of these curtains depends on the Weber number. If We < 1 (strong surface tension), the curtains bend upward against gravity. The article shows that these curtains are unstable and give rise to a downstream disturbance near the curtain's terminal point. It is argued that a properly positioned collection nozzle can stabilize the curtain. All curtains with We > 1 bend downward and are stable.
Article
Physics, Fluids & Plasmas
E. S. Benilov
Summary: This study examines the evaporation of a liquid layer on a substrate without assuming isothermality and considers temperature variations. Qualitative estimates demonstrate that nonisothermality affects the evaporation rate based on the substrate's conditions. If the substrate is thermally insulated, evaporative cooling significantly slows down evaporation to the point that the rate tends to zero with time and cannot be determined solely by measuring external parameters. However, if the substrate is maintained at a fixed temperature, the heat flux from below sustains evaporation at a finite rate, which can be deduced from fluid characteristics, relative humidity, and the layer's depth. The qualitative predictions are quantified using the diffuse-interface model applied to the evaporation of a liquid into its own vapor.
Article
Physics, Fluids & Plasmas
E. S. Benilov
Summary: In equilibrium, liquid and vapor are separated, but a liquid drop on a flat substrate evaporates. This conclusion is deduced using the diffuse-interface model and reformulated in terms of the maximum-entropy principle, showing model independence. Evaporation of drops is caused by the Kelvin effect, resulting in a liquid-to-vapor mass flux when the liquid phase boundary is convex.
Article
Mechanics
E. S. Benilov
Article
Physics, Fluids & Plasmas
E. S. Benilov
Article
Physics, Fluids & Plasmas
E. S. Benilov
Article
Mechanics
E. S. Benilov, M. S. Benilov
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2019)
Article
Physics, Fluids & Plasmas
E. S. Benilov, M. S. Benilov