scholarly journals On the statics and dynamics of fully confined bubbles

2017 ◽  
Vol 827 ◽  
pp. 194-224 ◽  
Author(s):  
Olivier Vincent ◽  
Philippe Marmottant

We investigate theoretically the statics and dynamics of bubbles in fully confined liquids, i.e. in liquids surrounded by solid walls in all directions of space. This situation is found in various natural and technological contexts (geological fluid inclusions, plant cells and vessels, soil tensiometers, etc.), where such bubbles can pre-exist in the trapped liquid or appear by nucleation (cavitation). We focus on volumetric deformations and first establish the potential energy of fully confined bubbles as a function of their radius, including contributions from gas compressibility, surface tension, liquid compressibility and elastic deformation of the surrounding solid. We evaluate how the Blake threshold of unstable bubble growth is modified by confinement and we also obtain an original bubble stability phase diagram with a regime of liquid superstability (spontaneous bubble collapse) for strong confinements. We then calculate the liquid velocity field associated with radial deformations of the bubble and strain in the solid, and we predict large deviations in the kinematics compared to bubbles in extended liquids. Finally, we derive the equations governing the natural oscillation dynamics of fully confined bubbles, extending Minnaert’s formula and the Rayleigh–Plesset equation, and we show that the compressibility of the liquid as well as the elasticity of the walls can result in ultra-fast bubble radial oscillations and unusually quick damping. We find excellent agreement between the predictions of our model and recent experimental results.

2012 ◽  
Vol 195 ◽  
pp. 169-172
Author(s):  
Bong Kyun Kang ◽  
Ji Hyun Jeong ◽  
Min Su Kim ◽  
Hong Seong Sohn ◽  
Ahmed A. Busnaina ◽  
...  

As the semiconductor manufacturing technology for ultra-high integration devices continue to shrink beyond 32 nm, stringent measures have to be taken to get damage free patterns during the cleaning process. The patterns are no longer cleaned with the megasonic (MS) irradiation in the advanced device node because of severe pattern damages caused by cleaning. Recently, several investigations are carried out to control the cavitation effects of megasonic to reduce the pattern damages. The mechanism of damage caused by an unstable acoustic bubble motion was mainly attributed to the high sound pressure associated with violent bubble collapse [1]. In order to characterize the dominant factors affecting the cavitation, MS cleaning was conducted with various dissolved gas concentrations in water. It was reported that the cavitation phenomena relating to particle removal efficiency (PRE) and pattern damage were considerably changed with the addition of a specific gas [2]. This changing behavior may be due to the difference in the physical properties of dissolved gases associated with acoustic bubble growth rate as a function of their concentration. In particular, cavitation effects induced during MS cleaning was controlled by adjusting the acoustic bubble growth rate. Also the change of bubble growth rate is well explained by both rectified diffusion for single bubble and bubble coalescence for multi-bubble, respectively. Similarly, it is well-known that surface active solute (SAS) in the ultrasound field plays an important role in controlling the cavitation effects. A detailed explanation of the acoustic bubble growth rate, cavitation threshold and their relationship with various types of SAS and concentration of biomedical and chemical reactions perspective have been reported elsewhere [3,4]. Their studies demonstrated that the change of cavitation effects depends not only on the chain length of alcohol in the solution but also on the physical properties such as surface tension and viscosity of SAS solutions.


e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Uday S. Agarwal

AbstractExisting approaches to simulate the bubble growth/collapse in viscoelastic liquids use the integral form of a constitutive equation, that can additionally be analytically integrated over the radial domain. Here we represent the process by a system of simultaneous partial differential equations, with fixed and finite boundaries. This enables a direct computer implementation with commercially available software, with little additional programming effort. The involved co-ordinate transformation preferably does not correspond to the material co-ordinates. The surrounding liquid can be simulated as being a finite film or of infinite extent, with simply a change in one computational parameter. We simulate hydrodynamically induced bubble dynamics in viscolelastic liquids, and estimate the flow strength (elongational strain rate) and its possible role in flow induced scission of polymer chains in liquids experiencing bubble collapse. Calculations are also performed to evaluate the influence of backbone and branch lengths when the surrounding fluid is a branched polymer melt, using the pom-pom model to describe the rheological behavior.


1968 ◽  
Vol 90 (1) ◽  
pp. 22-26 ◽  
Author(s):  
H. C. Hewitt ◽  
J. D. Parker

Experimental data on bubble growth in superheated liquid nitrogen, bubble collapse in subcooled liquid nitrogen, and bubble growth with decreasing liquid nitrogen pressure are compared to the theoretical solutions obtained for noncryogens. Vapor bubbles in liquid nitrogen were found to behave quite similarly to vapor bubbles in noncryogens. This paper provides experimental data in two areas where additional theoretical work is needed: Bubble collapse in subcooled liquid, and bubble growth with decreasing pressure.


Author(s):  
Yingyu Chen ◽  
Xiongliang Yao ◽  
Liangtao Liu ◽  
Ning Gan ◽  
Xiongwei Cui

Abstract In this paper, a coupling eulerian langarian method (CEL) is used to study the interaction between a collapsing underwater explosion bubble and a steel plate. The VOF method is used to simulate the physical process of bubble growth, contraction and collapse, while the finite element method is used to calculate dynamic response of the steel plate. By establishing the three dimensional numerical model, the study reveals the interesting insights into the complex problem of interaction a underwater explosion bubble and a steel plate, including the physical process of bubble growth, contraction and collapse, the dynamic response of the steel plate, as well as the wall pressure induced by the bubble dynamic. The results indicate that the elastic-plastic plate will generate permanent deformation loaded by the water jet; owing to the deformation of the nearby structure, the bubble shows as a “hazel” in the bubble contraction phase and forms toroidal jet which leads the bubble into several toroidal bubbles in the bubble collapse phase. This paper aim at proposing an effective numerical method which can be useful for the problem of strong interaction between bubble and structure.


2021 ◽  
Vol 928 ◽  
Author(s):  
J. Sakakeeny ◽  
C. Deshpande ◽  
S. Deb ◽  
J.L. Alvarado ◽  
Y. Ling

Accurate prediction of the natural frequency for the lateral oscillation of a liquid drop pinned on a vertical planar surface is important to many drop applications. The natural oscillation frequency, normalized by the capillary frequency, is mainly a function of the equilibrium contact angle and the Bond number ( $Bo$ ), when the contact lines remain pinned. Parametric numerical and experimental studies have been performed to establish a comprehensive understanding of the oscillation dynamics. An inviscid model has been developed to predict the oscillation frequency for wide ranges of $Bo$ and the contact angle. The model reveals the scaling relation between the normalized frequency and $Bo$ , which is validated by the numerical simulation results. For a given equilibrium contact angle, the lateral oscillation frequency decreases with $Bo$ , implying that resonance frequencies will be magnified if the drop oscillations occur in a reduced gravity environment.


2021 ◽  
Author(s):  
Guodong Ding ◽  
Jiaqing Chen ◽  
Zhenlin Li

Abstract Discrete bubbles can be effectively cracked and dispersed in a Venturi channel with its unique structural characteristics, and the general Venturi channel has been widely used in the practical engineering. Bubble breakup mechanisms based on Venturi channels have been extensively studied, but most of them are based on single bubble or bubble flow pattern. In this paper, the transport process of slug flow in a Venturi channel was explored through visualization experiments, and the characteristics of recirculation flow were indicated by numerical simulation method. The liquid velocity sensitively affects the bubble generation process. With the increase of the liquid velocity, the initial bubble is no longer detached from the gas injector hole, and the gas-liquid flow pattern changes from bubbly flow to slug flow. The slug bubble extends to the diverging section and experiences the process of interface instability, sub-bubble detachment and bubble collapse. The average Sauter bubble diameter decreases with the increase of liquid velocity, and the fitting function is Log Normal. There is a recirculation flow in the side wall region of the diverging section, and the area of the recirculation flow increases with the increase of the liquid velocity at the inlet. The numerical simulation results indicated that there is a large velocity gradient in the boundary region of the recirculation flow under slug flow pattern, which contribute to the bubble collapse.


Author(s):  
G. M. Hutchins ◽  
J. S. Gardner

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.


Author(s):  
Ann Cleary

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.


Author(s):  
M. Yamada ◽  
K. Ueda ◽  
K. Kuboki ◽  
H. Matsushima ◽  
S. Joens

Use of variable Pressure SEMs is spreading among electron microscopists The variable Pressure SEM does not necessarily require specimen Preparation such as fixation, dehydration, coating, etc which have been required for conventional scanning electron microscopy. The variable Pressure SEM allows operating Pressure of 1˜270 Pa in specimen chamber It does not allow microscopy of water-containing specimens under a saturated vapor Pressure of water. Therefore, it may cause shrink or deformation of water-containing soft specimens such as plant cells due to evaporation of water. A solution to this Problem is to lower the specimen temperature and maintain saturated vapor Pressures of water at low as shown in Fig. 1 On this technique, there is a Published report of experiment to have sufficient signal to noise ratio for scondary electron imaging at a relatively long working distance using an environmental SEM. We report here a new low temperature microscopy of soft Plant cells using a variable Pressure SEM (Hitachi S-225ON).


1992 ◽  
Vol 2 (5) ◽  
pp. 809-813 ◽  
Author(s):  
K Gordon ◽  
J Futterer ◽  
T Hohn

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