An Experimental Investigation of Bubble Motion i Turbulent Liquid Stream PDF Download
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Author: J. L. L. Baker
Publisher:
ISBN:
Category : Bubbles
Languages : en
Pages : 146
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Book Description
Author: J. L. L. Baker
Publisher:
ISBN:
Category : Bubbles
Languages : en
Pages : 146
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Book Description
Author: Zhentong Zhang (docteur en mécanique des fluides).)
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This thesis is devoted to the study of the motion of small bubbles in homogeneous isotropic turbulent flows. The work addresses several questions related to the statistical description of the hydrodynamic forces exerted on a bubble as well as the stochastic modeling of their high frequency fluctuations. First, we propose a model for the acceleration of micro-bubbles (smaller than the dissipative scale of the flow) subjected to the drag and the fluid inertia forces. This model, that depends on the Stokes number, the Reynolds number and the density ratio, reproduces the evolution of the acceleration variance as well as the relative importance and alignment of the two forces as observed from Direct Numerical Simulations (DNS). Second, based on the observation that acceleration statistics conditional to the local kinetic energy dissipation rate are invariant with the Stokes number and the dissipation rate, we propose a stochastic model for the instantaneous bubble acceleration vector accounting for the small-scale intermittency of the turbulent flows. The norm of the bubble acceleration is obtained by modeling the dissipation rate along the bubble trajectory from a log-normal stochastic process, whereas its orientation is given by two coupled random walk on a unit sphere in order to model the evolution of the joint orientation of the drag and inertia forces acting on the bubble. Furthermore, the proposed stochastic model for the bubble acceleration is used in the context of large eddy simulations (LES) of turbulent flows laden with small bubbles. It can effectively reproduce effect of turbulent motion at scales smaller than the mesh resolution by adding a random contribution depending on local average dissipation rate. Comparisons with DNS and standard LES, show that the proposed model improves significantly the statistics of the bubbly phase. Third, we extend the previous results in the case of bubbles with large Reynolds number by considering non-linear drag laws. We define an effective relaxation time based on the drag coefficient to characterize bubble motion (acceleration,velocity). Eventually we study the effect of buoyancy and lift force on the bubble dynamics, and analyze the reduction of the average rising velocity in turbulent flow compared to quiescent flows. It is observed that bubbles preferentially explore region having downward fluid acceleration which contributes through the inertia force to reduction of the rising velocity. In addition, as already observed, the lift force brings preferably bubbles into downstream fluid motion which also reduce their rising velocity.
Author: G. K. Batchelor
Publisher: Cambridge University Press
ISBN: 9780521041171
Category : Mathematics
Languages : en
Pages : 216
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Book Description
This is a reissue of Professor Batchelor's text on the theory of turbulent motion, which was first published by Cambridge Unviersity Press in 1953. It continues to be widely referred to in the professional literature of fluid mechanics, but has not been available for several years. This classic account includes an introduction to the study of homogeneous turbulence, including its mathematic representation and kinematics. Linear problems, such as the randomly-perturbed harmonic oscillator and turbulent flow through a wire gauze, are then treated. The author also presents the general dynamics of decay, universal equilibrium theory, and the decay of energy-containing eddies. There is a renewed interest in turbulent motion, which finds applications in atmospheric physics, fluid mechanics, astrophysics, and planetary science.
Author: Arie Biesheuvel
Publisher: Springer Science & Business Media
ISBN: 9401149860
Category : Technology & Engineering
Languages : en
Pages : 502
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Book Description
In Fascination of Fluid Dynamics contains a collection of papers by international experts in hydrodynamics, based on oral presentations at a symposium held in honour of Professor Leen van Wijngaarden on his 65th birthday. The book begins with a personal sketch of his life and scientific career. It continues with a mixture of papers that address recent developments in various branches of fluid mechanics. Many of the papers cover different aspects of multiphase flows: bubble dynamics, cavitation, bubbles and particles in turbulent flows, suspension flows, and wave phenomena in fluidised beds. Other topics that are addressed include: dynamics of jets, shock waves, MHD turbulence, selforganisation phenomena in 2D turbulence, vortex rings and the thermodynamics of tropical cyclones. This edited volume will be valuable reading for researchers, engineers and students interested in hydrodynamics, and in particular in multiphase flows.
Author: G. Bergeles
Publisher: Newnes
ISBN: 0444600132
Category : Technology & Engineering
Languages : en
Pages : 932
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Book Description
This book presents and discussses new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. At present, turbulence is one of the key issues in tackling engineering flow problems. Powerful computers and numerical methods are now available for solving the flow equations, but the simulation of turbulence effects which are nearly always important in practice, is still in an unsatisfactory state and introduces considerable uncertainities in the accuracy of CFD calculations. These and other aspects of turbulence modelling and measurements are dealt with in detail by experts in the field. The resulting book is an up-to-date review of the most recent research in this exciting area.
Author: R. Shankar Subramanian
Publisher: Cambridge University Press
ISBN: 9780521496056
Category : Science
Languages : en
Pages : 492
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Book Description
This 2001 book provides a thorough review of the motion of bubbles and drops in reduced gravity.
Author: Grétar Tryggvason
Publisher: Cambridge University Press
ISBN: 1139496700
Category : Computers
Languages : en
Pages : 337
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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.
Author: Z. Zapryanov
Publisher: Springer Science & Business Media
ISBN: 0792353471
Category : Technology & Engineering
Languages : en
Pages : 540
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Book Description
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.
Author: Eric Loth
Publisher: Cambridge University Press
ISBN: 1009365401
Category : Science
Languages : en
Pages : 574
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Book Description
A modern presentation of multiphase flow, from basic principles to state-of-the-art research. Explains dispersed fluid dynamics for bubbles, drops, or solid particles, incorporating detailed theory, experiments, simulations, and models while considering applications and recent cutting-edge advances. The book demonstrates the importance of multiphase flow in engineering and natural systems, considering particle size distributions, shapes and trajectories as well as deformation of fluid particles and multiphase flow numerical methods. The scope of the book also includes coupling physics between particles and turbulence through dispersion and modulation, and specific phenomena such as gravitational settling and collisions for solid particles, drops and bubbles. Featuring over eighty homework problems for each of the primary chapters, including theory-based and engineering application questions. The comprehensive coverage will give the reader a solid grounding for multiphase flow research and design, applicable to current and future engineering. This is an ideal resource for graduate students, researchers and professionals.
Author: John R. Blake
Publisher: Springer Science & Business Media
ISBN: 9401109389
Category : Science
Languages : en
Pages : 485
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Book Description
This volume contains papers presented at the IUTAM Symposium on Bubble Dynamics and Interface Phenomena held at the University of Birmingham from 6-9 September 1993. In many respects it follows on a decade later from the very successful IUTAM Symposium held at CALTECH in June 1981 on the Mechanics and physics of bubbles in liquids which was organised by the late Milton Plesset and Leen van Wijngaarden. The intervening period has seen major development with both experiment and theory. On the experimental side there have been ad vances with very high speed photography and data recording that provide detailed information on fluid and interface motion. Major developments in both computer hardware and software have also led to extensive improvement in our understand ing of bubble and interface dynamics although development is still limited by the sheer complexity of the laminar and turbulent flow regimes often associated with bubbly flows. The symposium attracts wide and extensive interest from engineers, physical, chemical, biological and medical scientists and applied mathematicians. The sci entific committee sought to achieve a balance between theory and experiment over a range of fields in bubble dynamics and interface phenomena. It was our intention to emphasise both the breadth and recent developments in these various fields and to encourage cross-fertilisation of ideas on both experimental techniques and theo retical developments. The programme, and the proceedings recorded herein, cover bubble dynamics, sound and wave propagation, bubbles in flow, sonoluminescence, acoustic cavitation, underwater explosions, bursting bubbles and ESWL.
