Download or read book Coherent Structures in Fully Developed Turbulent Pipe Flow written by Ioannis Constantinos Lekakis and published by . This book was released on 1988 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Behaviour of Energetic Coherent Structures in Turbulent Pipe Flow at High Reynolds Numbers written by Zeinab Hallol and published by Cuvillier Verlag. This book was released on 2021-10-26 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, coherent turbulent structures in turbulent pipe flow are investigated at relatively high Reynolds numbers and study their association in both total kinetic energy and Reynolds shear stress. Experimental investigations have been performed in Cottbus Large Pipe test facility (CoLaPipe) for pipe flow over a wide range of Reynolds number 8 × 104 ≤ ReD ≤ 1 × 106, located at the Aerodynamics and Fluid Mechanics Department, Brandenburg University of Technology Cottbus- Senftenberg (BTU). The first part of the thesis focuses on determining the contribution of the coherent structures using one-dimensional spectral analysis and assessing the structures behaviour in the outer region of pipe flow using high spatial resolution Hot-wire measurement up to 30kHz. The results of the power and pre-multiplied spectrum of stream-wise velocity indicate that the wavelength value of very large scale motions (VLSMs) acquires 19R at a maximum Reynolds number range ReD=1 × 106 (Reτ =19000). On the other hand, large-scale motions have a wavelength value of 3R over different Reynolds number range. Regarding the identified wavelength values, it is observed that contribution to energy for structures greater than 3R carries 55% of total kinetic energy. In addition, temporal-spatial resolution using the High-speed PIV measurements has been performed in CoLaPipe to estimate the contribution magnitude of stream-wise/wall-normal velocity fluctuations to total kinetic energy and Reynolds shear stress in the logarithmic and outer layer.
Download or read book Intermittency of Coherent Structures in the Core Region of Fully Developed Turbulent Pipe Flow written by Jean Sabot and published by . This book was released on 1976 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Interactions written by Michel Deville and published by Springer Science & Business Media. This book was released on 2009-03-20 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains seven keynote lectures of the TI 2006 conference that was held in Porquerolles, May 29-June 2, 2006. This book offers a view on theory, experiments and numerical simulations in the field of turbulence.
Download or read book A Dynamical System coherent Structure Approach to the Fully Developed Turbulent Wall Layer written by Nadine Aubry and published by . This book was released on 1987 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements with Particle Image Velocimetry on Fully Developed Turbulent Pipe Flow at Low Reynolds Number written by J. Westerweel and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements with particle image velocimetry were carried out in fully developed turbulent pipe flow at a Reynolds number of 5,277. Data were obtained in a plane through the centerline of the pipe, across the full diameter. Statistical properties of the flow obtained by ensemble averaging of the data along the axial direction were in good agreement with direct numerical simulation. Maps of instantaneous tangential vorticity reveal spatial structures near the pipe wall that resemble coherent flow structures predicted by direct numerical simulation. (Author).
Download or read book Engineering Turbulence Modelling and Experiments 4 written by D. Laurence and published by Elsevier. This book was released on 1999-04-14 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain the papers presented at the 4th International Symposium on Engineering Turbulence Modelling and Measurements held at Ajaccio, Corsica, France from 24-26 May 1999. It follows three previous conferences on the topic of engineering turbulence modelling and measurements. The purpose of this series of symposia is to provide a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. Turbulence is still one of the key issues in tackling engineering flow problems. As powerful computers and accurate numerical methods are now available for solving the flow equations, and since engineering applications nearly always involve turbulence effects, the reliability of CFD analysis depends more and more on the performance of the turbulence models. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation.
Download or read book Turbulence Coherent Structures Dynamical Systems and Symmetry written by Philip Holmes and published by Cambridge University Press. This book was released on 2012-02-23 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes methods revealing the structures and dynamics of turbulence for engineering, physical science and mathematics researchers working in fluid dynamics.
Download or read book Particle Image Velocimetry written by Ronald J. Adrian and published by Cambridge University Press. This book was released on 2011 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle image velocimetry, or PIV, refers to a class of methods used in experimental fluid mechanics to determine instantaneous fields of the vector velocity by measuring the displacements of numerous fine particles that accurately follow the motion of the fluid. Although the concept of measuring particle displacements is simple in essence, the factors that need to be addressed to design and implement PIV systems that achieve reliable, accurate, and fast measurements and to interpret the results are surprisingly numerous. The aim of this book is to analyze and explain them comprehensively.
Download or read book Turbulent coherent structures Secondary currents and Sediment ridges written by Scherer, Markus Maximilian and published by KIT Scientific Publishing. This book was released on 2024-06-19 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of secondary currents and subaqueous sediment patterns in natural rivers is analysed from first principles. For this purpose, simulations of sediment transport in canonical turbulent open channel flows are performed using a numerical technique that resolves all relevant flow scales and the dynamics of the individual sand grains. The high-fidelity datasets reveal the fundamental importance of individual coherent structures for the development of sediment patterns and secondary flows.
Download or read book Turbulence and Coherent Structures written by O. Métais and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 25 years, one of the most striking advances in Fluid Mecha nics was certainly the discovery of coherent structures in turbulence: lab oratory experiments and numerical simulations have shown that most turbulent flows exhibit both spatially-organized large-scale structures and disorganized motions, generally at smaller scales. The develop ment of new measurement and visualization techniques have allowed a more precise characterization and investigation of these structures in the laboratory. Thanks to the unprecedented increase of computer power and to the development of efficient interactive three-dimensional colour graphics, computational fluid dynamicists can explore the still myste rious world of turbulence. However, many problems remain unsolved concerning the origin of these structures, their dynamics, and their in teraction with the disorganized motions. In this book will be found the latest results of experimentalists, theoreticians and numerical modellers interested in these topics. These coherent structures may appear on airplane wings or slender bodies, mixing layers, jets, wakes or boundary-layers. In free-shear flows and in boundary layers, the results presented here highlight the intense three-dimensional character of the vortices. The two-dimensional large scale eddies are very sensitive to three-dimensional perturbations, whose amplification leads to the formation of three-dimensional coherent vorti cal structures, such as streamwise, hairpin or horseshoe vortex filaments. This book focuses on modern aspects of turbulence study. Relations between turbulence theory and optimal control theory in mathematics are discussed. This may have important applications with regard to, e. g. , numerical weather forecasting.
Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2019 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 Transport and Coherent Structures in Wall Turbulence written by Sedat Tardu and published by John Wiley & Sons. This book was released on 2014-10-06 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wall bounded turbulent flows are of major importance in industrial and environmental fluid mechanics. The structure of the wall turbulence is intrinsically related to the coherent structures that play a fundamental role in the transport process. The comprehension of their regeneration mechanism is indispensable for the development of efficient strategies in terms of drag control and near wall turbulence management. This book provides an up-to-date overview on the progress made in this specific area in recent years.
Download or read book Direct Numerical Simulation of Very Large Scale Motions in Turbulent Pipe Flow written by Christian Bauer and published by Cuvillier Verlag. This book was released on 2021-02-01 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Die turbulente Rohrströmung ist nicht nur von großer Bedeutung für Anwendungen im Ingenieurbereich, sondern auch für die Grundlagenforschung von wandnaher Turbulenz. In der vorliegenden Arbeit wird die Interaktion sogenannter turbulenter Superstrukturen (engl.: very-large-scale motions, VLSMs) mit der kleinskaligen Wandturbulenz auf Basis der Methode der direkten numerischen Simulation untersucht. Dabei werden Schubspannungs-Reynoldszahlen bis Reτ = 2880 und Rohrlängen bis L = 42R berücksichtigt. Es wird das Konvergenz- und Skalierungsverhalten verschiedener statistischer Momente der Geschwindigkeitsverteilung untersucht und in Bezug auf VLSMs diskutiert. Die folgende Analyse der axialen Energietransportgleichung des gefilterten Geschwindigkeitsfeldes legt offen, dass VLSMs Energie von der mittleren Strömung zugeführt bekommen, ähnlich den kleinskaligen Strukturen durch den turbulenten Produktionsmechanismus. Die verschiedenen Terme der Energiebilanz werden sowohl anhand von mittleren Profilen, als auch instantanen Strömungsvisualisierungen und drei-dimensionalen Korrelationen diskutiert, wobei auch auf das Phänomen der inversen turbulenten Energiekaskade eingegangen wird. Die Forschungsarbeit gewährt dabei neue Einblicke in die Interaktion der VLSMs mit dem turbulenten Wandzyklus und trägt zum besseren Verständnis der turbulenten Rohrströmung bei. Turbulent pipe flow is not only of importance to engineering applications but also of fundamental interest to the study of wall-bounded turbulence. In the present work, the interaction of the so-called very-large-scale motions (VLSMs) with the near-wall, small-scale turbulence is explored by means of direct numerical simulation for friction Reynolds numbers up to Reτ = 2880 and pipe lengths up to L = 42R. Besides, the convergence and the scaling of different order moments of the velocity distribution are studied and also discussed with regard to VLSMs. The subsequent analysis of the streamwise energy budget equation of the filtered velocity field reveals that VLSMs obtain their energy from the mean velocity field via a production mechanism similar to the one known from the near-wall cycle. Moreover, the different energy budget terms are investigated by means of statistical averages, instantaneous flow field visualisations, and three-dimensional correlations, wherein the backscattering phenomenon is also dealt with. In brief, the research sheds new light on our understanding of the interaction between VLSMs and the near-wall cycle and leads to a better grasp of turbulent pipe flow in general.
Download or read book Turbulence and Interactions written by Michel O. Deville and published by Springer. This book was released on 2017-09-11 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a snapshot of the state-of-art in the field of turbulence modeling, with an emphasis on numerical methods. Topics include direct numerical simulations, large eddy simulations, compressible turbulence, coherent structures, two-phase flow simulation and many more. It includes both theoretical contributions and experimental works, as well as chapters derived from keynote lectures, presented at the fourth Turbulence and Interactions Conference (TI 2015), which was held on June 11-14 in Cargèse, Corsica, France. This multifaceted collection, which reflects the conference ́s emphasis on the interplay of theory, experiments and computing in the process of understanding and predicting the physics of complex flows and solving related engineering problems, offers a timely guide for students, researchers and professionals in the field of applied computational fluid dynamics, turbulence modeling and related areas.
Download or read book Theoretical and Applied Mechanics 1992 written by S.R. Bodner and published by Elsevier. This book was released on 2012-12-02 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contained in this volume are the full texts of the invited general and sectional lectures presented at this conference concerning mechanics and its development. The entire field of mechanics is covered, including analytical, solid and fluid mechanics and their applications. A brilliant survey of work in the fields of fluid and solid mechanics is also given. The papers are written by leading experts which is reflected in the quality and diversity of the lectures and posters presented, they will provide a valuable key to the latest and most important developments in the various sub-fields of mechanics.
Download or read book Fully Developed Periodic Turbulent Pipe Flow Part 2 The Detailed Structure of the Flow written by B. R. Ramaprian and published by . This book was released on 1983 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
