Cavitation and Bubble Dynamics


Book Description

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




Some Environmental Effects on Headform Cavitation Inception


Book Description

Cavitation-inception tests were performed on two headforms for which changes were made in the environment. Quantities which were varied, included type and amount of dissolved gas, chemical additives, time rate of change to cause inception, and temperature changes. Experimental procedure and relative air content had an appreciable effect on cavitation inception. Both headforms had the same designed minimum pressure coefficient; however, for one it was located 0.03 diam from the nose, and for the other, 0.73 diam. Inception was characterized by traveling bubbles on both headforms, with significant differences occurring in the bubble dynamics. Inception was determined visually and by counting occurrences.




Direct Numerical Simulations of Gas–Liquid Multiphase Flows


Book Description

Accurately predicting the behaviour of multiphase flows is a problem of immense industrial and scientific interest. Modern computers can now study the dynamics in great detail and these simulations yield unprecedented insight. This book provides a comprehensive introduction to direct numerical simulations of multiphase flows for researchers and graduate students. After a brief overview of the context and history the authors review the governing equations. A particular emphasis is placed on the 'one-fluid' formulation where a single set of equations is used to describe the entire flow field and interface terms are included as singularity distributions. Several applications are discussed, showing how direct numerical simulations have helped researchers advance both our understanding and our ability to make predictions. The final chapter gives an overview of recent studies of flows with relatively complex physics, such as mass transfer and chemical reactions, solidification and boiling, and includes extensive references to current work.




Bubble Nucleation and Dynamics


Book Description

For phenomena involving bubble nucleation, the molecular cluster model is used to predict the tensile strength and superheat limit of liquids and the amount of decompression for gaseous bubble nucleation in supersaturated solutions. The book investigates various gaseous bubble nucleation events including the bubble formation in gas-water solutions, CO bubble formation in iron melts, the formation of microcellular foams in polymers, the nucleation of nano-sized H2O bubbles in rhyolite melts, and bubble nucleation in shear flow fields. The book also investigates vaporous bubble nucleation events such as bubble formation on a cavity-free surface and inside a solid nanopore in 3M NaCl solution, superheat limit of liquids, and bubble nucleation near the absolute zero temperature by quantum tunnelling in liquid helium. For bubble dynamics phenomena, a set of homologous solutions of the Navier-Stokes equations for evolving spherical bubbles are used to treat gaseous bubble growth in organic solutions, polymer solutions, and in viscous rhyolitic melts. The growth and collapse of laser-induced vapor bubbles in liquid, and on solid particles is discussed as an example of homologous motion of the spherical object. Sonoluminescence phenomena in water and in sulfuric acid solutions, the pressure and shock wave propagation in bubbly mixtures, the gravitational collapse of Newtonian stars, and the core collapse of supernovas are also treated using these homologous solutions. The motion of a fire-ball generated by a TNT explosion underwater is obtained using a zero gravitational constant in the equation of motion for Newtonian stars.




Gas Bubble Dynamics in the Human Body


Book Description

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










Acoustic Cavitation and Bubble Dynamics


Book Description

This brief explains in detail fundamental concepts in acoustic cavitation and bubble dynamics, and describes derivations of the fundamental equations of bubble dynamics in order to support those readers just beginning research in this field. Further, it provides an in-depth understanding of the physical basis of the phenomena. With regard to sonochemistry, the brief presents the results of numerical simulations of chemical reactions inside a bubble under ultrasound, especially for a single-bubble system and including unsolved problems. Written so as to be accessible both with and without prior knowledge of fundamental fluid dynamics, the brief offers a valuable resource for students and researchers alike, especially those who are unfamiliar with this field. A grasp of fundamental undergraduate mathematics such as partial derivative and fundamental integration is advantageous; however, even without any background in mathematics, readers can skip the equations and still understand the fundamental physics of the phenomena using the book’s wealth of illustrations and figures. As such, it is also suitable as an introduction to the field.