Numerical Simulation of Vortex Breakdown
Author : Jasim Uddin Ahmad
Publisher :
Page : 318 pages
File Size : 42,8 MB
Release : 1989
Category : Fluid dynamics
ISBN :
Numerical Simulation of Vortex Breakdown by the Vortex-filament Method
Author : Y. Nakamura
Publisher :
Page : 20 pages
File Size : 27,52 MB
Release : 1983
Category : Numerical analysis
ISBN :
Book Description
The vortex-filament method was applied to the simulation of vortex breakdown. The principal vortex region was represented by multiple filaments, and an axial velocity component was induced by a spiral winding of the filaments. First, an accuracy check was performed for a cylindrical swirling flow field that can be simulated to any accuracy by increasing the number of filaments. Second, an axisymmetric-type vortex breakdown was simulated, with experimental data serving asupstream conditions. The calculated axial- and theta-velocity contours show the breakdown of the vortex, including a rapid change in the vortex core, followed axially by a recovery zone and then a second breakdown. When three-dimensional initial data are used the second breakdown appears to be out of the spiral type in correspondence with experimental observations. The present method can easily be used to simulate other types of vortex breakdown or other vortex flows with axial velocity.
Ames Research Center
Author :
Publisher :
Page : 4 pages
File Size : 27,44 MB
Release : 1968
Category : Aeronautics
ISBN :
Book Description
Fluid Vortices
Author : Sheldon Green
Publisher : Springer Science & Business Media
Page : 905 pages
File Size : 17,21 MB
Release : 2012-12-06
Category : Technology & Engineering
ISBN : 940110249X
Book Description
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.
DESider – A European Effort on Hybrid RANS-LES Modelling
Author : Werner Haase
Publisher : Springer Science & Business Media
Page : 469 pages
File Size : 12,22 MB
Release : 2009-05-12
Category : Technology & Engineering
ISBN : 3540927735
Book Description
Preface “In aircraft design, efficiency is determined by the ability to accurately and rel- bly predict the occurrence of, and to model the development of, turbulent flows. Hence, the main objective in industrial computational fluid dynamics (CFD) is to increase the capabilities for an improved predictive accuracy for both complex flows and complex geometries”. This text part taken from Haase et al (2006), - scribing the results of the DESider predecessor project “FLOMANIA” is still - and will be in future valid. With an ever-increasing demand for faster, more reliable and cleaner aircraft, flight envelopes are necessarily shifted into areas of the flow regimes exhibiting highly unsteady and, for military aircraft, unstable flow behaviour. This undou- edly poses major new challenges in CFD; generally stated as an increased pred- tive accuracy whist retaining “affordable” computation times. Together with highly resolved meshes employing millions of nodes, numerical methods must have the inherent capability to predict unsteady flows. Although at present, (U)RANS methods are likely to remain as the workhorses in industry, the DESider project focussed on the development and combination of these approaches with LES methods in order to “bridge” the gap between the much more expensive (due to high Reynolds numbers in flight), but more accurate (full) LES.
Topology-Based Methods in Visualization II
Author : Hans-Christian Hege
Publisher : Springer Science & Business Media
Page : 194 pages
File Size : 26,99 MB
Release : 2009-02-07
Category : Mathematics
ISBN : 3540886060
Book Description
Visualization research aims to provide insight into large, complicated data sets and the phenomena behind them. While there are di?erent methods of reaching this goal, topological methods stand out for their solid mathem- ical foundation, which guides the algorithmic analysis and its presentation. Topology-based methods in visualization have been around since the beg- ning of visualization as a scienti?c discipline, but they initially played only a minor role. In recent years,interest in topology-basedvisualization has grown andsigni?cantinnovationhasledto newconceptsandsuccessfulapplications. The latest trends adapt basic topological concepts to precisely express user interests in topological properties of the data. This book is the outcome of the second workshop on Topological Methods in Visualization, which was held March 4–6, 2007 in Kloster Nimbschen near Leipzig,Germany.Theworkshopbroughttogethermorethan40international researchers to present and discuss the state of the art and new trends in the ?eld of topology-based visualization. Two inspiring invited talks by George Haller, MIT, and Nelson Max, LLNL, were accompanied by 14 presentations by participants and two panel discussions on current and future trends in visualization research. This book contains thirteen research papers that have been peer-reviewed in a two-stage review process. In the ?rst phase, submitted papers where peer-reviewed by the international program committee. After the workshop accepted papers went through a revision and a second review process taking into account comments from the ?rst round and discussions at the workshop. Abouthalfthepapersconcerntopology-basedanalysisandvisualizationof ?uid?owsimulations;twopapersconcernmoregeneraltopologicalalgorithms, while the remaining papers discuss topology-based visualization methods in application areas like biology, medical imaging and electromagnetism.
Liutex and Its Applications in Turbulence Research
Author : Chaoqun Liu
Publisher : Academic Press
Page : 460 pages
File Size : 34,49 MB
Release : 2020-10-29
Category : Technology & Engineering
ISBN : 0128190248
Book Description
Liutex and Its Applications in Turbulence Research reviews the history of vortex definition, provides an accurate mathematical definition of vortices, and explains their applications in flow transition, turbulent flow, flow control, and turbulent flow experiments. The book explains the term "Rortex" as a mathematically defined rigid rotation of fluids or vortex, which could help solve many longstanding problems in turbulence research. The accurate mathematical definition of the vortex is important in a range of industrial contexts, including aerospace, turbine machinery, combustion, and electronic cooling systems, so there are many areas of research that can benefit from the innovations described here. This book provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence. Important theory and methodologies used for developing these laws are described in detail, including: the classification of the conventional turbulent boundary layer concept based on proper velocity scaling; the methodology for identification of the scales of velocity, temperature, and length needed to establish the law; and the discovery, proof, and strict validations of the laws, with both Reynolds and Prandtl number independency properties using DNS data. The establishment of these statistical laws is important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence. - Provides an accurate mathematical definition of vortices - Provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence - Explains the term "Rortex as a mathematically defined rigid rotation of fluids or vortex - Covers the statistical laws important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence
Experimental Study of Vortex Breakdown in a Cylindrical, Swirling Flow
Author : José L. Stevens
Publisher :
Page : 142 pages
File Size : 22,49 MB
Release : 1996
Category : Aerodynamics
ISBN :
Book Description
Vortex Dynamics
Author : P. G. Saffman
Publisher : Cambridge University Press
Page : 332 pages
File Size : 20,49 MB
Release : 1995-02-24
Category : Mathematics
ISBN : 9780521477390
Book Description
Vortex dynamics is a natural paradigm for the field of chaotic motion and modern dynamical system theory. However, this volume focuses on those aspects of fluid motion that are primarily controlled by the vorticity and are such that the effects of the other fluid properties are secondary.
Unsteady Combustor Physics
Author : Tim C. Lieuwen
Publisher : Cambridge University Press
Page : 427 pages
File Size : 44,85 MB
Release : 2012-08-27
Category : Technology & Engineering
ISBN : 1139576836
Book Description
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.
