Instability and Pattern Formation of Thin Liquid Films Sandwiched between Soft Elastomer Layers

2013 ◽  
Vol 745-746 ◽  
pp. 417-423
Author(s):  
Ling Qiao ◽  
Fu Ying Tan
Keyword(s):  
Growth Rate ◽  
Fluid Layer ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Wave Number ◽  
Critical Wave Number ◽  
Periodic Surface ◽  
Surface Buckling ◽  
Solid Liquid ◽  
Soft Elastomer

The surface instability of trilayer films consisting of a fluid layer sandwiched in between the two thin elastomer capping layers was studied. The solid-liquid-solid sandwiched films will form well-defined periodic surface buckling spontaneously. In the present study, the flow of the sandwiched liquid layer was approximated by the theory of lubrication. The elastic capping films was modeled with the nonlinear theory of a thin plate. A linear stability analysis identified the growth rate and the critical wave number of the surface undulation of trilayer films. The analysis showed that applied deformation in the capping layers regulated the surface buckling and resulted in well-defined periodic surface corrugation with tunable wavelength. The result of this study may provide a mechanism to control the morphology of the films in a mechanical way.

scholarly journals Effects of Suction–Injection–Combination (SIC) on the onset of Rayleigh–Bénard Electroconvection in a Micropolar Fluid

2015 ◽  
Vol 14 (3) ◽  
pp. 23-42 ◽  
Author(s):  
S Pranesh ◽  
Tarannum Sameena ◽  
Baby Riya
Keyword(s):  
Stability Analysis ◽  
Micropolar Fluid ◽  
Fluid Layer ◽  
Suspended Particles ◽  
Wave Number ◽  
Critical Wave Number ◽  
Onset Of Convection ◽  
Temperature Boundary ◽  
The Stability ◽  
Rayleigh Benard

The effect of Suction – injection combination on the onset of Rayleigh – Bénard electroconvection micropolar fluid is investigated by making a linear stability analysis. The Rayleigh-Ritz technique is used to obtain the eigenvalues for different velocity and temperature boundary combinations. The influence of various parameters on the onset of convection has been analysed. It is found that the effect of Prandtl number on the stability of the system is dependent on the SIC being pro-gravity or anti-gravity. A similar Pe-sensitivity is found in respect of the critical wave number. It is observed that the fluid layer with suspended particles heated from below is more stable compared to the classical fluid layer without suspended particles.

scholarly journals Nucleated dewetting in supported ultra-thin liquid films with hydrodynamic slip

Soft Matter ◽  
2017 ◽  
Vol 13 (27) ◽  
pp. 4756-4760 ◽  
Author(s):  
Matthias Lessel ◽  
Joshua D. McGraw ◽  
Oliver Bäumchen ◽  
Karin Jacobs
Keyword(s):  
Boundary Condition ◽  
Surface Energy ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Thin Polymer Films ◽  
Breakup Mechanism ◽  
Thin Polymer ◽  
Hydrodynamic Slip ◽  
Liquid Boundary ◽  
Solid Liquid

This study reveals the influence of the surface energy and solid/liquid boundary condition on the breakup mechanism of dewetting ultra-thin polymer films.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

HEAT TRANSFER IN THIN LIQUID FILMS FLOWING DOWN HEATED INCLINED GROOVED PLATES

2010 ◽  
Vol 2 (5) ◽  
pp. 455-468 ◽  
Author(s):  
Hongyi Yu ◽  
Karsten Loffler ◽  
Tatiana Gambaryan-Roisman ◽  
Peter Stephan
Keyword(s):  
Heat Transfer ◽  
Liquid Films ◽  
Thin Liquid Films

scholarly journals Evaporation-driven solutocapillary flow of thin liquid films over curved substrates

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Mariana Rodríguez-Hakim ◽  
Joseph M. Barakat ◽  
Xingyi Shi ◽  
Eric S. G. Shaqfeh ◽  
Gerald G. Fuller
Keyword(s):  
Liquid Films ◽  
Thin Liquid Films

scholarly journals Controlling the breakup of toroidal liquid films on solid surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew M. J. Edwards ◽  
Élfego Ruiz-Gutiérrez ◽  
Michael I. Newton ◽  
Glen McHale ◽  
Gary G. Wells ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Mode Selection ◽  
Liquid Films ◽  
Solid Surfaces ◽  
Final States ◽  
Digital Microfluidic ◽  
Insulating Liquid ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Dynamics Stability

AbstractThe breakup of a slender filament of liquid driven by surface tension is a classical fluid dynamics stability problem that is important in many situations where fine droplets are required. When the filament is resting on a flat solid surface which imposes wetting conditions the subtle interplay with the fluid dynamics makes the instability pathways and mode selection difficult to predict. Here, we show how controlling the static and dynamic wetting of a surface can lead to repeatable switching between a toroidal film of an electrically insulating liquid and patterns of droplets of well-defined dimensions confined to a ring geometry. Mode selection between instability pathways to these different final states is achieved by dielectrophoresis forces selectively polarising the dipoles at the solid-liquid interface and so changing both the mobility of the contact line and the partial wetting of the topologically distinct liquid domains. Our results provide insights into the wetting and stability of shaped liquid filaments in simple and complex geometries relevant to applications ranging from printing to digital microfluidic devices.

scholarly journals Two-layer modeling of thermally induced Bénard convection in thin liquid films: Volume of fluid approach vs thin-film model

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045317
Author(s):  
Ali Mohammadtabar ◽  
Hadi Nazaripoor ◽  
Adham Riad ◽  
Arman Hemmati ◽  
Mohtada Sadrzadeh
Keyword(s):  
Thin Film ◽  
Volume Of Fluid ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Thermally Induced ◽  
Film Model ◽  
Bénard Convection ◽  
Thin Film Model ◽  
Benard Convection

Film Elasticity and Film Stabilization in Firefighting Foam Stabilized by Solid Particles

2017 ◽  
Vol 744 ◽  
pp. 346-349
Author(s):  
Xiu Juan Li ◽  
Rui Song Guo ◽  
Min Zhao
Keyword(s):  
Life Time ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Solid Particles ◽  
High Concentration ◽  
Hydration Effect ◽  
Fixed Area ◽  
The Stability ◽  
Hydration Layers ◽  
Hydration Forces

The structure of the thin liquid films determines the stability of foams and emulsions. In this work the bubbles stretched length with different hollow SiO2 particles concentration is measured when the foam has been stilled for different time. The results show that the bubbles stretched length is longer than that of bubbles when the foam is free of hollow SiO2 particles even when the foam has been stilled for 500mins. The bubbles stretched length increases with increasing the concentration of hollow SiO2 particles. A strong hydration effect leaves a large volume of hydration layers on the solid particles surfaces in aqueous solutions. The water in hydration layers can help the film keep a certain thickness. The existence of hydration forces leads that two particles cannot be too close each other. The high concentration surfactant limited in the fixed area helps the film keep good elasticity. Therefore the film has a long life time with compatible thickness and elasticity and the three-phrase foam is upper stable.

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