Gas Bubble Dynamics in the Human Body

Gas Bubble Dynamics in the Human Body
Author: Saul Goldman
Publisher: Academic Press
Total Pages: 322
Release: 2017-09-28
Genre: Medical
ISBN: 0128105208

Gas Bubble Dynamics in the Human Body provides a broad range of professionals, from physicians working in a clinic, hospital or hyperbaric facility, to physical scientists trying to understand and predict the dynamics of gas bubble behavior in the body, with an interdisciplinary perspective on gas-bubble disease. Both iatrogenic and decompression-induced gas bubbles are considered. The basic medical and physiological aspects are described first, in plain language, with numerous illustrations that facilitate an intuitive grasp of the basic underlying medicine and physiology. Current issues in the field, particularly microbubbles and microparticles, and their possible role in gas-bubble disease are included. The physical and mathematical material is given at several levels of sophistication, with the "hard-core" math separated out in sections labelled "For the Math Mavens", so that the basic concepts can be grasped at a descriptive level. The field is large and multi-disciplinary, so that some of the discussion that is at a greater depth is given separately in sections labelled "In Greater Detail". Skipping these sections for whatever reason, shouldn’t materially hamper acquiring an overall appreciation of the field. Demonstrates how physical and mathematical tools help to solve underlying problems across physiology and medicine Helps researchers extend their competence and flexibility to the point that they can personally contribute to the field of hyperbaric medicine and physiology, or to other related biological problems that may interest them Provides clinicians with explicit examples of how mathematical modelling can be integrated into clinical treatment and decision-making

Dynamics of Bubbles, Drops and Rigid Particles

Dynamics of Bubbles, Drops and Rigid Particles
Author: Z. Zapryanov
Publisher: Springer Science & Business Media
Total Pages: 540
Release: 1998-12-31
Genre: Technology & Engineering
ISBN: 0792353471

1. Objective and Scope Bubbles, drops and rigid particles occur everywhere in life, from valuable industrial operations like gas-liquid contracting, fluidized beds and extraction to such vital natural processes as fermentation, evaporation, and sedimentation. As we become increasingly aware of their fundamental role in industrial and biological systems, we are driven to know more about these fascinating particles. It is no surprise, therefore, that their practical and theoretical implications have aroused great interest among the scientific community and have inspired a growing number of studies and publications. Over the past ten years advances in the field of small Reynolds numbers flows and their technological and biological applications have given rise to several definitive monographs and textbooks in the area. In addition, the past three decades have witnessed enormous progress in describing quantitatively the behaviour of these particles. However, to the best of our knowledge, there are still no available books that reflect such achievements in the areas of bubble and drop deformation, hydrodynamic interactions of deformable fluid particles at low and moderate Reynolds numbers and hydrodynamic interactions of particles in oscillatory flows. Indeed, only one more book is dedicated entirely to the behaviour of bubbles, drops and rigid particles ["Bubbles, Drops and Particles" by Clift et al. (1978)] and the authors state its limitations clearly in the preface: "We treat only phenomena in which particle-particle interactions are of negligible importance. Hence, direct application of the book is limited to single-particle systems of dilute suspensions.

A Level Set Numerical Method to Determine the Dynamics of Gas Bubbles in Inclined Channels

A Level Set Numerical Method to Determine the Dynamics of Gas Bubbles in Inclined Channels
Author: Catherine Eleanor Norman
Publisher:
Total Pages:
Release: 2005
Genre:
ISBN:

The dynamics of a gas bubble rising in vertical and inclined channels is investigated. The solution of this free boundary problem is determined numerically by using a level set method coupled with a finite difference solution of the Navier-Stokes equations. The numerical method is second order in space. Both two- and three-dimensional results will be discussed as a function of Reynolds number, Bond number, and inclination angle. Steady solutions are found for small values of all these parameters, and path and shape oscillations are observed as these parameters are increased. The effect of inclination angle is investigated for freely rising bubbles and for bubbles initially attached to the channel wall. In the latter case, the contact line problem is solved by introducing a Navier slip boundary condition along with a fixed contact angle. The bubble is observed to rupture at high Bond numbers. At high Reynolds numbers, when the inclination angle is also above a critical value, the steady solution is found to bifurcate into a time-periodic oscillation. The results presented here parallel experimental work that has found a critical inclination angle at which the dynamics changes from steadily rising bubbles to bouncing bubbles. Three-dimensional simulations have been conducted for bubbles in vertical channels. At higher Reynolds number, the initially spherical bubble deforms into an oblate ellipsoidal shape, and a path instability is found when the bubble's aspect ratio exceeds a critical threshold. The density and viscosity ratios between the bubble and the suspending fluid are varied and are found to affect the bubble dynamics. In addition, the bubble's wake is visualized, and a double-threaded wake of counter-rotating vortex filaments is observed behind a zigzagging bubble.

A Parametric Investigation of Gas Bubble Growth and Pinch-off Dynamics from Capillary-tube Orifices in Liquid Pools

A Parametric Investigation of Gas Bubble Growth and Pinch-off Dynamics from Capillary-tube Orifices in Liquid Pools
Author: Deepak Saagar Kalaikadal
Publisher:
Total Pages: 125
Release: 2012
Genre:
ISBN:

The air-bubble dynamics phenomena in adiabatic liquid pools has been studied so as to present a better understanding of the parameters which that govern the process of ebullience, bubble growth and departure from a submerged capillary-tube orifice. The orifice diameter is found to directly dictate the bubble departure diameter, and the pinch-off is controlled by a characteristic neck-length. To study the role of orifice size on the growth and departure of adiabatic single bubbles, experiments were performed with different diameter capillary tubes submerged in of distilled de-ionized water as well as some other viscous liquids. A correlation has been developed based on the experimental data of this study along with those reported by several others in the literature. The predictions of this correlation agree very well with measured data for water as well as several other more viscous liquids. It is also found that the bubble departure diameter is the same as the orifice diameter when the latter equals twice the capillary length. The phenomenon of bubble necking and departure was explored experimentally and through a scaling analysis. Experiments were performed with five different liquids (water, ethanol, ethylene glycol, propylene glycol, and glycerol) to extract the departure neck-lengths for isolated gas bubbles at pinch-off from the capillary orifice. A scaling analysis of the experimental data indicated that the bubble neck-length at departure or pinch-off was predicted by a balance of buoyancy, viscous and surface tension forces. These were established to be represented by the Galilei and Morton numbers, and a power-law type predictive correlation has been shown to be in excellent agreement with the available data over a wide range of liquid properties. To characterize and model the growth and departure of single bubbles in different liquid pools, a theoretical model has been established. The motion of the gas-liquid interface has been modeled as a scaled force balance involving buoyancy, gas-momentum, pressure, surface tension, inertia and drag. With one-dimensional scaling of these forces, the model captures the incipience, growth, necking and departure of a bubble as it emerges from the orifice. Here necking and pinch-off is modeled based on the newly developed neck-length correlation. The results are compared with experimental data and are found to be in excellent agreement for a range of liquids, orifice sizes and flow rates. The predictions highlight the variations in bubble equivalent diameters at departure with orifice sizes, flow rates and fluid properties, and they further reiterate the well-established two-regime theory of bubble growth. The latter involves (a) the constant volume regime, where the bubble volume remains near constant and relatively independent of flow rate, and (b) the growing bubble regime, where the size of the bubble increases proportionately with the gas flow rate. Finally, the complex nature of ebullience in aqueous surfactant solutions has been studied using the reagents FS-50, SDS, and CTAB. The influence of the modulated liquid surface tension or more specifically, the role of the time dependent dynamic surface tension on the formation and departure of adiabatic bubbles has been investigated. Comparative studies have been undertaken to investigate the effect of time-dependent surface tension relaxation in surfactant solutions as opposed to ebullience in pure liquids with the same equilibrium surface tensions. Results highlight the effects of the surfactant's molecular weight on the adsorption-desorption kinetics, and the consequent influence on ebullience. It has been established that the bubbling characteristics in surfactant solutions are, in the first order, governed by the dynamic surface tension of the solute-solvent system.

Cavitation and Bubble Dynamics

Cavitation and Bubble Dynamics
Author: Christopher E. Brennen
Publisher: Cambridge University Press
Total Pages: 269
Release: 2014
Genre: Mathematics
ISBN: 1107644763

Cavitation and Bubble Dynamics deals with fundamental physical processes of bubble dynamics and cavitation for graduate students and researchers.