Download or read book Numerical Study of the Non Oberbeck Boussinesq Effects in Turbulent Water filled Cavities written by Deniz Kizildag and published by . This book was released on 2016 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work carried out in the framework of the present thesis aims at shedding light into the complex phenomena involved in turbulent water-filled cavities, questioning the validity of the well-established Oberbeck-Boussinesq effects, and determining the influence of these on the flow structure and heat transfer. First, the relevance of the variable thermophyical properties have been submitted to investigation by means of direct numerical simulations of a differentially heated cavity flow using the aspect ratio of a particular prototype. The simulations consider the so-called non-Oberbeck-Boussinesq effects, and study the temperature range for which these effects could be considered relevant. The work has been conducted employing a 2D flow assumption, estimating that this methodology -promoted by the necessity of a compromise between the accuracy and the cost of the simulations- would be valid to detect the non-Oberbeck-Boussinesq effects without the loss of generality, even though the actual flow structures of the flow are inherently 3D. The numerical results have revealed that up to the temperature difference of 30 oC, Oberbeck-Boussinesq solution can estimate the heat transfer within 1 % error, although the loss of symmetry is certified even for a temperature difference of 10 oC. Moreover, it has been observed that the boundary layers at hot and cold isothermal confining walls behave differently, such that the boundary layer instabilities and transition to turbulence location move downstream along the hot wall and upstream along the cold wall. As a consequence, the stratification region shifts upwards, giving rise to higher stratification numbers. Later, the non-Oberbeck-Boussinesq effects have been studied considering three-dimensional domain by means of direct numerical simulations, in the quest of analyzing their impact on the three-dimensional flow structure. The results have revealed delayed transition in the hot wall and earlier triggered transition in the cold wall boundary layers. This has been shown to be a consequence of the initial heating of the cavity due to favorable heat transfer properties in the hot wall boundary layer, which results in warmer upper cavity. As time advances, due to the influence of the stratified flow feeding the hot and cold boundary layers, the strength of the natural convection gradually decreases and increases in the hot and cold boundary layers, respectively. When a balance is attained between these two boundary layers, the cold wall boundary is found at a higher equivalent Rayleigh number, justifying its premature transition. Accordingly, the early transitioning cold wall boundary layer is thicker. This boundary layer interacts actively with the hot wall boundary layer, causing vertical oscillations in the transition to turbulent locations on both boundary layers. This interaction is also responsible for the degradation of the already shifted stratification zone. Besides the qualitative agreement in some aspects, this important effect is not captured by means of 2D simulations, which invalidates 2D flow hypothesis when it comes to describing the flow characteristics with non-Oberbeck-Boussinesq effects. As for the heat transfer, the Non-Oberbeck-Boussinesq effects do not necessarily enhance the heat transfer, as Oberbeck-Boussinesq solution is observed to overestimate the Nusselt number by about 3 %. Last but not the least, considering the huge computational resources required for simulating these turbulent natural convection flows with water, and bearing in mind the importance of an appropriate modeling of the present phenomena, different subgrid-scale models have been analyzed in order to predict the thermal and fluid dynamics of the flow within a turbulent water-filled cavity. It has been shown that the performance of the models is directly linked to the accurate prediction of the transition to turbulence, which is the main challenge in the proper modeling of this flow.
Download or read book Natural Convection in a Square Cavity written by Graham De Vahl Davis and published by . This book was released on 1982 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Engineering Heat Transfer written by G. F. Nellis and published by Cambridge University Press. This book was released on 2020-07-30 with total page 1027 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equips students with the essential knowledge, skills, and confidence to solve real-world heat transfer problems using EES, MATLAB, and FEHT.
Download or read book Energy Information Abstracts written by and published by . This book was released on 1988 with total page 968 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 1991 with total page 1380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1987 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer to Non Newtonian Fluids written by Aroon Shenoy and published by John Wiley & Sons. This book was released on 2018-03-12 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been written with the idea of providing the fundamentals for those who are interested in the field of heat transfer to non-Newtonian fluids. It is well recognized that non-Newtonian fluids are encountered in a number of transport processes and estimation of the heat transfer characteristics in the presence of these fluids requires analysis of equations that are far more complex than those encountered for Newtonian fluids. A deliberate effort has been made to demonstrate the methods of simplification of the complex equations and to put forth analytical expressions for the various heat transfer situations in as vivid a manner as possible. The book covers a broad range of topics from forced, natural and mixed convection without and with porous media. Laminar as well as turbulent flow heat transfer to non-Newtonian fluids have been treated and the criterion for transition from laminar to turbulent flow for natural convection has been established. The heat transfer characteristics of non-Newtonian fluids from inelastic power-law fluids to viscoelastic second-order fluids and mildly elastic drag reducing fluids are covered. This book can serve the needs of undergraduates, graduates and industry personnel from the fields of chemical engineering, material science and engineering, mechanical engineering and polymer engineering.
Download or read book Fluid Mechanics written by L D Landau and published by Elsevier. This book was released on 2013-09-03 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Mechanics, Second Edition deals with fluid mechanics, that is, the theory of the motion of liquids and gases. Topics covered range from ideal fluids and viscous fluids to turbulence, boundary layers, thermal conduction, and diffusion. Surface phenomena, sound, and shock waves are also discussed, along with gas flow, combustion, superfluids, and relativistic fluid dynamics. This book is comprised of 16 chapters and begins with an overview of the fundamental equations of fluid dynamics, including Euler's equation and Bernoulli's equation. The reader is then introduced to the equations of motion of a viscous fluid; energy dissipation in an incompressible fluid; damping of gravity waves; and the mechanism whereby turbulence occurs. The following chapters explore the laminar boundary layer; thermal conduction in fluids; dynamics of diffusion of a mixture of fluids; and the phenomena that occur near the surface separating two continuous media. The energy and momentum of sound waves; the direction of variation of quantities in a shock wave; one- and two-dimensional gas flow; and the intersection of surfaces of discontinuity are also also considered. This monograph will be of interest to theoretical physicists.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1989 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Convection in Porous Media written by D.A. Nield and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book we have tried to provide a user-friendly introduction to the topic of convection in porous media. We have assumed that the reader is conversant with the basic elements of fluid mechanics and heat transfer, but otherwise the book is self-contained. Only routine classical mathematics is employed. We hope that the book will be useful both as a review (for reference) and as a tutorial work (suitable as a textbook in a graduate course or seminar). This book brings into perspective the voluminous research that has been performed during the last two decades. The field has recently exploded because of worldwide concern with issues such as energy self-sufficiency and pollution of the environment. Areas of application include the insulation of buildings and equipment, energy storage and recovery, geothermal reservoirs, nuclear waste disposal, chemical reactor engineering, and the storage of heat-generating materials such as grain and coal. Geophysical applications range from the flow of groundwater around hot intrusions to the stability of snow against avalanches.
Download or read book Thermal Convection written by Marcello Lappa and published by John Wiley & Sons. This book was released on 2009-11-05 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Convection - Patterns, Stages of Evolution and Stability Behavior provides the reader with an ensemble picture of the subject, illustrating the state-of-the-art and providing the researchers from universities and industry with a basis on which they are able to estimate the possible impact of a variety of parameters. Unlike earlier books on the subject, the heavy mathematical background underlying and governing the behaviors illustrated in the text are kept to a minimum. The text clarifies some still unresolved controversies pertaining to the physical nature of the dominating driving force responsible for asymmetric/oscillatory convection in various natural phenomena and/or technologically important processes and can help researchers in elaborating and validating new, more complex models, in accelerating the current trend towards predictable and reproducible natural phenomena and in establishing an adequate scientific foundation to industrial processes. Thermal Convection - Patterns, Stages of Evolution and Stability Behavior is intended as a useful reference guide for specialists in disciplines such as the metallurgy and foundry field and researchers and scientists who are now coordinating their efforts to improve the quality of semiconductor or macromolecular crystals. The text may also be of use to organic chemists and materials scientists, atmosphere and planetary physicists, as well as an advanced level text for students taking part in courses on the physics of fluids, fluid mechanics, the behavior and evolution of non-linear systems, environmental phenomena and materials engineering.
Download or read book Direct and Large Eddy Simulation XII written by Manuel García-Villalba and published by Springer Nature. This book was released on 2020-05-09 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 12th instalment in the bi-annual Workshop series on Direct and Large Eddy Simulation (DLES), which began in 1994 and focuses on modern techniques used to simulate turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structure. With the rapidly expanding capacities of modern computers, this approach has attracted more and more interest over the years and will undoubtedly be further enhanced and applied in the future. Hybrid modelling techniques based on a combination of LES and RANS approaches also fall into this category and are covered as well. The goal of the Workshop was to share the state of the art in DNS, LES and related techniques for the computation and modelling of turbulent and transitional flows. The respective papers highlight the latest advances in the prediction, understanding and control of turbulent flows in academic and industrial applications.
Download or read book Chaos Complexity And Transport Theory And Applications Proceedings Of The Cct 07 written by Xavier Leoncini and published by World Scientific. This book was released on 2008-05-27 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to provide the readers with a wide panorama of different aspects related to Chaos, Complexity and Transport. It consists of a collection of contributions ranging from applied mathematics to experiments, presented during the CCT'07 conference (Marseilles, June 4-8, 2007). The book encompasses different traditional fields of physics and mathematics while trying to keep a common language among the fields, and targets a nonspecialized audience.
Download or read book Handbook of Porous Media written by Kambiz Vafai and published by CRC Press. This book was released on 2005-03-30 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last three decades, advances in modeling flow, heat, and mass transfer through a porous medium have dramatically transformed engineering applications. Comprehensive and cohesive, Handbook of Porous Media, Second Edition presents a compilation of research related to heat and mass transfer including the development of practical applications
Download or read book Recent Trends in Mathematical Modeling and High Performance Computing written by Vinai K. Singh and published by Springer Nature. This book was released on 2021-08-23 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume explores the connections between mathematical modeling, computational methods, and high performance computing, and how recent developments in these areas can help to solve complex problems in the natural sciences and engineering. The content of the book is based on talks and papers presented at the conference Modern Mathematical Methods and High Performance Computing in Science & Technology (M3HPCST), held at Inderprastha Engineering College in Ghaziabad, India in January 2020. A wide range of both theoretical and applied topics are covered in detail, including the conceptualization of infinity, efficient domain decomposition, high capacity wireless communication, infectious disease modeling, and more. These chapters are organized around the following areas: Partial and ordinary differential equations Optimization and optimal control High performance and scientific computing Stochastic models and statistics Recent Trends in Mathematical Modeling and High Performance Computing will be of interest to researchers in both mathematics and engineering, as well as to practitioners who face complex models and extensive computations.
Download or read book Natural Convection from Circular Cylinders written by Sandra K. S. Boetcher and published by Springer. This book was released on 2014-08-05 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a concise, yet thorough, reference for all heat transfer coefficient correlations and data for all types of cylinders: vertical, horizontal, and inclined. This book covers all natural convection heat transfer laws for vertical and inclined cylinders and is an excellent resource for engineers working in the area of heat transfer engineering.
Download or read book Theory and Modeling of Rotating Fluids written by Keke Zhang and published by Cambridge University Press. This book was released on 2017-05-23 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic account of the theory and modelling of rotating fluids that highlights the remarkable advances in the area and brings researchers and postgraduate students in atmospheres, oceanography, geophysics, astrophysics and engineering to the frontiers of research. Sufficient mathematical and numerical detail is provided in a variety of geometries such that the analysis and results can be readily reproduced, and many numerical tables are included to enable readers to compare or benchmark their own calculations. Traditionally, there are two disjointed topics in rotating fluids: convective fluid motion driven by buoyancy, discussed by Chandrasekhar (1961), and inertial waves and precession-driven flow, described by Greenspan (1968). Now, for the first time in book form, a unified theory is presented for three topics - thermal convection, inertial waves and precession-driven flow - to demonstrate that these seemingly complicated, and previously disconnected, problems become mathematically simple in the framework of an asymptotic approach that incorporates the essential characteristics of rotating fluids.
