Download or read book A Quantitative Analysis of Starting Jet Vortex Ring Entrainment at Low Reynolds Number written by Alex Geoffrey Dulude and published by . This book was released on 2007 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The future propulsion of very small unmanned air and underwater vehicles operating at Reynolds numbers in the hundreds or less may be accomplished by pulsing a jet of fluid rather than more conventional methods of propulsion such as propellers and turbo jets as used by large-scale vehicles. Pulse jet propulsion produces trailing vortex rings and recent research concerning the formation and evolution of vortex rings has suggested that these structures may be exploited to augment the thrust and increase the efficiency of pulsed jet propulsion. Limited studies have indicated correlations between the length and shape of the generating pulse and the formation, fluid entrainment, and thrust augmentation provided by the resultant vortex ring at ring Reynolds number as low as approximately 13,000. The onset of vortex ring pinch-off has previously been shown to be a limit to this thrust augmentation. The design, construction, and implementation of a novel, piston-cylinder-type, vortex ring generator to confirm and further improve measurements of fluid entrainment and other formation characteristics has been accomplished. This apparatus was used in dye injection studies and stereoscopic particle image velocimetry (SPIV) studies to qualitatively examine the evolution of the vortex ring, and evaluate the effects of pulse length and shape on the formation of the vortex ring over a range of Reynolds numbers between 250 and 13,000. Results from this investigation at a Reynolds number of 13,000 are in close agreement with those of previous research, indicating that pulse shaping can delay the phenomena of vortex ring pinch-off by as much as 20% of the stroke length to diameter ratio. Results from lower Reynolds numbers show a trending toward even greater delay of pinch-off, as Reynolds number decreases. Tests conducted at Re=250 indicate a delay in pinch-off in excess of 400% over that seen at Re=13,000.
Download or read book Vortex Rings and Jets written by Daniel T. H. New and published by Springer. This book was released on 2015-03-26 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, recent developments in our understanding of fundamental vortex ring and jet dynamics will be discussed, with a view to shed light upon their near-field behaviour which underpins much of their far-field characteristics. The chapters provide up-to-date research findings by their respective experts and seek to link near-field flow physics of vortex ring and jet flows with end-applications in mind. Over the past decade, our knowledge on vortex ring and jet flows has grown by leaps and bounds, thanks to increasing use of high-fidelity, high-accuracy experimental techniques and numerical simulations. As such, we now have a much better appreciation and understanding on the initiation and near-field developments of vortex ring and jet flows under many varied initial and boundary conditions. Chapter 1 outlines the vortex ring pinch-off phenomenon and how it relates to the initial stages of jet formations and subsequent jet behaviour, while Chapter 2 takes a closer look at the behaviour resulting from vortex ring impingement upon solid boundaries and how the use of a porous surface alters the impingement process. Chapters 3 and 4 focus upon the formation of synthetic jets from vortex ring structures experimentally and numerically, the challenges in understanding the relationships between their generation parameters and how they can be utilized in flow separation control problems. Chapter 5 looks at the use of imposing selected nozzle trailing-edge modifications to effect changes upon the near-field dynamics associated with circular, noncircular and coaxial jets, with a view to control their mixing behaviour. And last but not least, Chapter 6 details the use of unique impinging jet configurations and how they may lend themselves towards greater understanding and operating efficacies in heat transfer problems. This book will be useful to postgraduate students and researchers alike who wish to get up to speed regarding the latest developments in vortex ring and jet flow behaviour and how their interesting flow dynamics may be put into good use in their intended applications.
Download or read book An Investigaion of the Vortex Wake and Induced Entrainment for a Jet in Low Reynolds Number Cross Flow written by Peter J. Butkewicz and published by . This book was released on 1970 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Rings written by D. G. Akhmetov and published by Springer Science & Business Media. This book was released on 2009-11-24 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex flow is one of the fundamental types of fluid and gas motion. These flows are the most spectacular in the form of concentrated vortices, characterized by the localization of vorticity (curl of velocity) in bounded regions of a space, beyond which the vorticity is either absent or rapidly falls down to zero. Concentrated vortices are often observed in nature, exemplified by atmospheric cyclones, whirlwinds and tornados, oceanic vortices, whirlpools on a water s- face, and ring vortices caused by explosive outburst of volcanoes. In technical - vices concentrated vortices form when flow separates from sharp edges of flying vehicles and ships. Among these are vortices flowing off the ends of airplane wings, and intentionally generated vortices for intensification of burning in c- bustion chambers, vortices in cyclonic devices used for mixing or separation of impurities in fluids and gases. One such remarkable and frequent type of conc- trated vortices is a vortex ring which constitutes a vortex tube closed into a t- oidal ring moving in a surrounding fluid like an isolated body out of contact with solid boundaries of the flow region if such boundaries exist. Formation and motion of vortex rings are important part of the dynamics of a continuum medium and have been studied for more than a century.
Download or read book Journal of Experimental Biology written by and published by . This book was released on 2005 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1968 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2018-12-13 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master the theory, applications and control mechanisms of flow control techniques.
Download or read book Turbulent Jets and Plumes written by Joseph Hun-wei Lee and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets and plumes are shear flows produced by momentum and buoyancy forces. Examples include smokestack emissions, fires and volcano eruptions, deep sea vents, thermals, sewage discharges, thermal effluents from power stations, and ocean dumping of sludge. Knowledge of turbulent mixing by jets and plumes is important for environmental control, impact and risk assessment. Turbulent Jets and Plumes introduces the fundamental concepts and develops a Lagrangian approach to model these shear flows. This theme persists throughout the text, starting from simple cases and building towards the practically important case of a turbulent buoyant jet in a density-stratified crossflow. Basic ideas are illustrated by ample use of flow visualization using the laser-induced fluorescence technique. The text includes many illustrative worked examples, comparisons of model predictions with laboratory and field data, and classroom tested problems. An interactive PC-based virtual-reality modelling software (VISJET) is also provided. Engineering and science students, researchers and practitioners may use the book both as an introduction to the subject and as a reference in hydraulics and environmental fluid mechanics.
Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantized Vortices in Helium II written by Russell J. Donnelly and published by Cambridge University Press. This book was released on 1991-03-07 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the properties of quantized vortex lines in superfluid helium-4 in the light of research on vortices in modern fluid mechanics, and gives the first comprehensive treatment of the problem. The author's comprehensive approach will make this book invaluable for students taking advanced undergraduate or graduate courses, and for all those involved in research on classical and quantum vortices.
Download or read book Fluid Vortices written by Sheldon Green and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 905 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). The book can also be recommended as an advanced graduate-level supplementary textbook. The first nine chapters of the book are suitable for a one-term course; chapters 10--19 form the basis for a second one-term course.
Download or read book Mathematical Reviews written by and published by . This book was released on 2007 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Visualization written by Alexander J. Smits and published by World Scientific. This book was released on 2012 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the 2nd edition of the book, Flow Visualization: Techniques and Examples, which was published by Imperial College Press in 2000. Many of the chapters have been revised and updated to take into consideration recent changes in a number of flow visualization and measurement techniques, including an updated high quality flow gallery. Unique among similar publications, this book focuses on the practical rather than theoretical aspects. Obtaining high quality flow visualization results is, in many ways, more of an art than a science, and experience plays a key deciding role. The depth and breadth of the material will make this book invaluable to readers of all levels of experience in the field.
Download or read book The 3rd International Microgravity Combustion Workshop written by and published by . This book was released on 1995 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulus Dynamics written by Chao Jih-Ping and published by . This book was released on 1969 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Gallery of Fluid Motion written by M. Samimy and published by Cambridge University Press. This book was released on 2004-01-12 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The visualization of fluid flow has played a major role in the development of fluid dynamics and its applications, from the evolution of flight to tracking weather, and understanding the flow of blood. The Fluid Dynamics Division of the American Physical Society sponsors an annual competition for outstanding images of fluid flow. This volume includes a selection of winners from 1985 to the present. Each image is accompanied by some explanatory text, making the volume an important acquisition for anyone involved in fluid flow research.
