Download or read book Numerical Modeling of Bedform Development in Turbulent Flows written by Quoc Y. Nguyen and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of river bedform under interactions with water flows is a complex process due to turbulence of the flow and continuous change of bed geometry. In this study, the problem was examined by numerical computations. Two latest advanced tools of Computational Fluid Mechanics, namely Large-Eddy-Simulation and Immersed-Boundary-Method, were employed. Flows were turbulent at low Reynolds number and treated in three-dimensions. Bed surfaces was treated as continuos medium rather than individual sediment particles. The results showed strong correlations between change of the bed surface and the shear tress applied by the flows. Development of bedform from initially flat bed to full-size sandwaves had been observed from the computations. Experimentally observed phenomena, such as development of ripple train, was also successfully reproduced.
Download or read book Simulation and Modeling of Turbulent Flows written by Thomas B. Gatski and published by Oxford University Press. This book was released on 1996-07-11 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.
Download or read book Numerical Modeling of Turbulent Flow in a Channel written by You-wei Dai and published by . This book was released on 1983 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence Modelling Approaches written by Konstantin Volkov and published by BoD – Books on Demand. This book was released on 2017-07-26 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of turbulent flows remains a challenging task despite considerable work in this area and the acceptance of CFD as a design tool. The quality of the CFD calculations of the flows in engineering applications strongly depends on the proper prediction of turbulence phenomena. Investigations of flow instability, heat transfer, skin friction, secondary flows, flow separation, and reattachment effects demand a reliable modelling and simulation of the turbulence, reliable methods, accurate programming, and robust working practices. The current scientific status of simulation of turbulent flows as well as some advances in computational techniques and practical applications of turbulence research is reviewed and considered in the book.
Download or read book Physical and Numerical Modeling of Turbulent Open Channel Flow Over Different Bed Forms written by Yunhan Zheng and published by . This book was released on 1997 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Flows written by Jean Piquet and published by Springer Science & Business Media. This book was released on 2001-03-26 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.
Download or read book Modeling and Simulation of Turbulent Flows written by Roland Schiestel and published by John Wiley & Sons. This book was released on 2010-01-05 with total page 751 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title provides the fundamental bases for developing turbulence models on rational grounds. The main different methods of approach are considered, ranging from statistical modelling at various degrees of complexity to numerical simulations of turbulence. Each of these various methods has its own specific performances and limitations, which appear to be complementary rather than competitive. After a discussion of the basic concepts, mathematical tools and methods for closure, the book considers second order closure models. Emphasis is placed upon this approach because it embodies potentials for clarifying numerous problems in turbulent shear flows. Simpler, generally older models are then presented as simplified versions of the more general second order models. The influence of extra physical parameters is also considered. Finally, the book concludes by examining large Eddy numerical simulations methods. Given the book’s comprehensive coverage, those involved in the theoretical or practical study of turbulence problems in fluids will find this a useful and informative read.
Download or read book Numerical Modeling of Turbulent Flow in a Channel written by Y. W. Dai and published by . This book was released on 1983 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book DNS of Wall Bounded Turbulent Flows written by Tapan K. Sengupta and published by Springer. This book was released on 2019-02-09 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights by careful documentation of developments what led to tracking the growth of deterministic disturbances inside the shear layer from receptivity to fully developed turbulent flow stages. Associated theoretical and numerical developments are addressed from basic level so that an uninitiated reader can also follow the materials which lead to the solution of a long-standing problem. Solving Navier-Stokes equation by direct numerical simulation (DNS) from the first principle has been considered as one of the most challenging problems of understanding what causes transition to turbulence. Therefore, this book is a very useful addition to advanced CFD and advanced fluid mechanics courses.
Download or read book Numerical Modeling of Turbulent Flow in Open Channel Bends written by Jorge Gustavo Gutierrez and published by . This book was released on 1998 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Theory and Modeling for Turbulent Flows written by P. A. Durbin and published by Wiley. This book was released on 2001-02-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most natural and industrial flows are turbulent. The atmosphere and oceans, automobile and aircraft engines, all provide examples of this ubiquitous phenomenon. In recent years, turbulence has become a very lively area of scientific research and application, and this work offers a grounding in the subject of turbulence, developing both the physical insight and the mathematical framework needed to express the theory. Providing a solid foundation in the key topics in turbulence, this valuable reference resource enables the reader to become a knowledgeable developer of predictive tools. This central and broad ranging topic would be of interest to graduate students in a broad range of subjects, including aeronautical and mechanical engineering, applied mathematics and the physical sciences. The accompanying solutions manual to the text also makes this a valuable teaching tool for lecturers and for practising engineers and scientists in computational and experimental and experimental fluid dynamics.
Download or read book Development of high fidelity numerical methods for turbulenti flows simulation written by Francesco Capuano and published by . This book was released on 2015 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aquananotechnology written by David E. Reisner and published by CRC Press. This book was released on 2014-09-24 with total page 1370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world’s fresh water supplies are dwindling rapidly—even wastewater is now considered an asset. By 2025, most of the world's population will be facing serious water stresses and shortages. Aquananotechnology: Global Prospects breaks new ground with its informative and innovative introduction of the application of nanotechnology to the remediation of contaminated water for drinking and industrial use. It provides a comprehensive overview, from a global perspective, of the latest research and developments in the use of nanotechnology for water purification and desalination methods. The book also covers approaches to remediation such as high surface area nanoscale media for adsorption of toxic species, UV treatment of pathogens, and regeneration of saturated media with applications in municipal water supplies, produced water from fracking, ballast water, and more. It also discusses membranes, desalination, sensing, engineered polymers, magnetic nanomaterials, electrospun nanofibers, photocatalysis, endocrine disruptors, and Al13 clusters. It explores physics-based phenomena such as subcritical water and cavitation-induced sonoluminescence, and fog harvesting. With contributions from experts in developed and developing countries, including those with severe contamination, such as China, India, and Pakistan, the book’s content spans a wide range of the subject areas that fall under the aquananotechnology banner, either squarely or tangentially. The book strongly emphasizes sorption media, with broad application to a myriad of contaminants—both geogenic and anthropogenic—keeping in mind that it is not enough for water to be potable, it must also be palatable.
Download or read book Turbulent Flows written by Jean Piquet and published by Springer. This book was released on 2014-03-12 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt: obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.
Download or read book Constructive Modeling of Structural Turbulence and Hydrodynamic Instabilities written by Oleg Mikha?lovich Belot?serkovski? and published by World Scientific. This book was released on 2009 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides an original approach in the research of structural analysis of free developed shear compressible turbulence at high Reynolds number on the base of direct numerical simulation (DNS) and instability evolution for ideal medium (integral conservation laws) with approximate mechanism of dissipation (FLUX dissipative monotone ?upwind? difference schemes) and does not use any explicit sub-grid approximation and semi-empirical models of turbulence. Convective mixing is considered as a principal part of conservation law.Appropriate hydrodynamic instabilities (free developed shear turbulence) are investigated from unique point of view. It is based on the concept of large ordered structures with stochastic core of small scale developed turbulence (?turbulent spot?). Decay of ?turbulent spot? are simulated by Monte Carlo method. Proposed approach is based on two hypotheses: statistical independence of the characteristic of large ordered structures (LOS) and small-scale turbulence (ST) ?and? weak influence of molecular viscosity (or more generally, dissipative mechanism) on properties of large ordered structures.Two versions of instabilities, due to Rayleigh-Taylor and Richtmyer-Meshkov are studied detail by the three-dimensional calculations, extended to the large temporal intervals, up to turbulent stage and investigation turbulent mixing zone (TMZ).The book covers both the fundamental and practical aspects of turbulence and instability and summarizes the result of numerical experiments conducted over 30 years period with direct participation of the author.In the book are cited the opinions of the leading scientists in this area of research: Acad. A S Monin (Russia), Prof. Y Nakamura (Japan, Nagoya University) and Prof. F Harlow (USA, Los-Alamos).
Download or read book Experimental and Numerical Investigation of Developing Turbulent Flow Over a Wavy Wall written by Vinicius Martins Segunda and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent flow over a wavy wall in a horizontal channel is investigated by experimental and numerical methods. The thorough problem understanding can advance turbulent flow physics knowledge for separating and reattaching flows. Another important consideration is the performance evaluation of mathematical models used in computational fluid dynamics (CFD) codes to predict the flow characteristics. This study explores numerical models because they are critically important to the design and performance evaluation of engineering systems. The experimental data are obtained to provide repository data and more insights into the flow physics considering both the flow development and fully periodic regions. A channel with a wavy bottom wall is considered for this study, and its main characteristic is a value of 10 for the ratio between the wave length and wave amplitude. A high-resolution particle image velocimetry (PIV) system is used to obtain detailed measurements of velocity at Reynolds number of 5040, 8400, 10700 and 13040 in both the developing and fully periodic regions. The numerical simulations are performed with a commercial CFD code using four eddy viscosity turbulence models and three Second-Moment Closure (SMC) turbulence models. This work assessed the predictive accuracy of a total of seven turbulence models. The experimental study covered a lack of data for the flow development within the waves, prior the periodic condition region, and it supported the turbulence models evaluation. The experiments provided features of the flow such as the recirculation regions, Reynolds stresses, and turbulent kinetic energy production at different channel locations. A comprehensive comparison between models and experimental data revealed a significant dependency on the turbulence model formulation and on the wall treatment selection for the flow development and fully periodic regions predictions.
Download or read book Mathematical and Numerical Foundations of Turbulence Models and Applications written by Tomás Chacón Rebollo and published by Birkhäuser. This book was released on 2016-08-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With applications to climate, technology, and industry, the modeling and numerical simulation of turbulent flows are rich with history and modern relevance. The complexity of the problems that arise in the study of turbulence requires tools from various scientific disciplines, including mathematics, physics, engineering and computer science. Authored by two experts in the area with a long history of collaboration, this monograph provides a current, detailed look at several turbulence models from both the theoretical and numerical perspectives. The k-epsilon, large-eddy simulation and other models are rigorously derived and their performance is analyzed using benchmark simulations for real-world turbulent flows. Mathematical and Numerical Foundations of Turbulence Models and Applications is an ideal reference for students in applied mathematics and engineering, as well as researchers in mathematical and numerical fluid dynamics. It is also a valuable resource for advanced graduate students in fluid dynamics, engineers, physical oceanographers, meteorologists and climatologists.
