Download or read book Studies of the Structure of Turbulence by High resolution Simulation and Theory written by and published by . This book was released on 1998 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project was a study of structures of fluid turbulence using high-resolution direct numerical simulation and the theory development based on observations and measurements on the numerical simulations. Significant advances have been made in the study of fundamental fluid turbulence through numerical and theoretical work. The research has been focussed on the following areas: (1) The dynamics of advected passive scalar: Using the equations of motion, we analytically predict the anomalous scaling exponents for a passive scalar advected by fluid turbulence. The exponents are verified through large-scale simulation with 81922 mesh points. This is the first case in which anomalous scaling exponents for a turbulence problem have been deduced from the equations of motion. (2) The inertial range scaling in three-dimensional (3D) turbulence: High-resolution direct numerical simulations of 3D Navier-Stokes turbulence with normal viscosity and hyperviscosity are carried out to study the inertial-range statistics. It is found that both the scalings and the probability distribution functions are independent of the dissipation mechanism, but the near-dissipation-range fluctuations show significant structural differences; (3) Statistics and structures of pressure field, vorticity, and dissipation in three-dimensional incompressible isotropic turbulence have been studied. The statistical relations among pressure, vorticity, dissipation, and kinetic energy are investigated using a conditional averaging process; and (4) The refined similarity hypothesis: We studied the conditionally averaged velocity increments as a function of the locally averaged dissipation. Our results provide direct evidence in support of the refined similarity hypotheses.
Download or read book Research Directions in Computational Mechanics written by National Research Council and published by National Academies Press. This book was released on 1991-02-01 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational mechanics is a scientific discipline that marries physics, computers, and mathematics to emulate natural physical phenomena. It is a technology that allows scientists to study and predict the performance of various productsâ€"important for research and development in the industrialized world. This book describes current trends and future research directions in computational mechanics in areas where gaps exist in current knowledge and where major advances are crucial to continued technological developments in the United States.
Download or read book Turbulence and Interactions written by Michel Deville and published by Springer. This book was released on 2014-11-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strongly Anisotropic Turbulence, Statistical Theory and DNS.- Compressible Turbulence in Interactions of Supersonic Flows.- Universality in Statistics at Small Scales of Turbulence: A Study by High Resolution DNS.- Supersonic and Hypersonic Boundary-Layer Flows.- Studies of Bubbly Channel Flows by Direct Numerical Simulations.- Large Eddy Simulations of Turbulent Combustion.- Exact Coherent Structures in Turbulent Shear Flows.
Download or read book Interstellar Turbulence written by José Franco and published by Cambridge University Press. This book was released on 1999-05-28 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely volume presents a series of review articles covering every aspect of interstellar turbulence--from accretion disks, molecular clouds, atomic and ionized media, through to spiral galaxies - based on a major international conference held in Mexico City.With advances in observational techniques and the development of more efficient computer codes and faster computers, research in this area has made spectacular progress in recent years. This book provides a comprehensive overview of the most important developments in observing and modelling turbulent flows in the cosmos. It provides graduate student and researchers with a state-of-the-art summary of observational, theoretical and computational research in interstellar turbulence.
Download or read book Turbulence Models and Their Application in Hydraulics written by Wolfgang Rodi and published by . This book was released on 1984 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studying Turbulence Using Numerical Simulation Databases written by Center for Turbulence Research (U.S.) and published by . This book was released on 1987 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Marine Turbulence written by Helmut Z. Baumert and published by Cambridge University Press. This book was released on 2005-04-04 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive overview of marine turbulence and mixing for students, scientists, engineers.
Download or read book Advanced Approaches in Turbulence written by Paul Durbin and published by Elsevier. This book was released on 2021-07-24 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Approaches in Turbulence: Theory, Modeling, Simulation and Data Analysis for Turbulent Flows focuses on the updated theory, simulation and data analysis of turbulence dealing mainly with turbulence modeling instead of the physics of turbulence. Beginning with the basics of turbulence, the book discusses closure modeling, direct simulation, large eddy simulation and hybrid simulation. The book also covers the entire spectrum of turbulence models for both single-phase and multi-phase flows, as well as turbulence in compressible flow. Turbulence modeling is very extensive and continuously updated with new achievements and improvements of the models. Modern advances in computer speed offer the potential for elaborate numerical analysis of turbulent fluid flow while advances in instrumentation are creating large amounts of data. This book covers these topics in great detail. Covers the fundamentals of turbulence updated with recent developments Focuses on hybrid methods such as DES and wall-modeled LES Gives an updated treatment of numerical simulation and data analysis
Download or read book Direct Numerical Simulations DNS of Turbulent Flows in an Undulating Channel written by Luo Wang and published by . This book was released on 2007 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: In summary, in this work we have developed and successfully tested all the necessary ingredients for a successful simulation of viscoelastic turbulent flow in a wavy channel. It is only a matter of time in future work to address the fine tuning of parameters such as the diffusivity, time integration scheme, etc. in order to successfully perform the very large scale simulations needed to reproduce viscoelastic turbulent flows in a wavy channel flow geometry.
Download or read book Los Alamos Science written by and published by . This book was released on 2005 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical and Numerical Foundations of Turbulence Models and Applications written by Tomás Chacón Rebollo and published by Springer. This book was released on 2014-06-17 with total page 530 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.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993-08 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Complex Turbulent Flows written by Manuel D. Salas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence modeling both addresses a fundamental problem in physics, 'the last great unsolved problem of classical physics,' and has far-reaching importance in the solution of difficult practical problems from aeronautical engineering to dynamic meteorology. However, the growth of supercom puter facilities has recently caused an apparent shift in the focus of tur bulence research from modeling to direct numerical simulation (DNS) and large eddy simulation (LES). This shift in emphasis comes at a time when claims are being made in the world around us that scientific analysis itself will shortly be transformed or replaced by a more powerful 'paradigm' based on massive computations and sophisticated visualization. Although this viewpoint has not lacked ar ticulate and influential advocates, these claims can at best only be judged premature. After all, as one computational researcher lamented, 'the com puter only does what I tell it to do, and not what I want it to do. ' In turbulence research, the initial speculation that computational meth ods would replace not only model-based computations but even experimen tal measurements, have not come close to fulfillment. It is becoming clear that computational methods and model development are equal partners in turbulence research: DNS and LES remain valuable tools for suggesting and validating models, while turbulence models continue to be the preferred tool for practical computations. We believed that a symposium which would reaffirm the practical and scientific importance of turbulence modeling was both necessary and timely.
Download or read book The Atmosphere over Mountainous Regions written by Miguel A. C. Teixeira and published by Frontiers Media SA. This book was released on 2016-11-09 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mountainous regions occupy a significant fraction of the Earth's continents and are characterized by specific meteorological phenomena operating on a wide range of scales. Being a home to large human populations, the impact of mountains on weather and hydrology has significant practical consequences. Mountains modulate the climate and create micro-climates, induce different types of thermally and dynamically driven circulations, generate atmospheric waves of various scales (known as mountain waves), and affect the boundary layer characteristics and the dispersion of pollutants. At the local scale, strong downslope winds linked with mountain waves (such as the Foehn and Bora) can cause severe damage. Mountain wave breaking in the high atmosphere is a source of Clear Air Turbulence, and lee wave rotors are a major near-surface aviation hazard. Mountains also act to block strongly stratified air layers, leading to the formation of valley cold air-pools (with implications for road safety, pollution, crop damage, etc.) and gap flows. Presently, neither the fine-scale structure of orographic precipitation nor the initiation of deep convection by mountainous terrain can be resolved adequately by regional-to global-scale models, requiring appropriate downscaling or parameterization. Additionally, the shortest mountain waves need to be parameterized in global weather and climate prediction models, because they exert a drag on the atmosphere. This drag not only decelerates the global atmospheric circulation, but also affects temperatures in the polar stratosphere, which control ozone depletion. It is likely that both mountain wave drag and orographic precipitation lead to non-trivial feedbacks in climate change scenarios. Measurement campaigns such as MAP, T-REX, Materhorn, COLPEX and i-Box provided a wealth of mountain meteorology field data, which is only starting to be explored. Recent advances in computing power allow numerical simulations of unprecedented resolution, e.g. LES modelling of rotors, mountain wave turbulence, and boundary layers in mountainous regions. This will lead to important advances in understanding these phenomena, as well as mixing and pollutant dispersion over complex terrain, or the onset and breakdown of cold air pools. On the other hand, recent analyses of global circulation biases point towards missing drag, especially in the southern hemisphere, which may be due to processes currently neglected in parameterizations. A better understanding of flow over orography is also crucial for a better management of wind power and a more effective use of data assimilation over complex terrain. This Research Topic includes contributions that aim to shed light on a number of these issues, using theory, numerical modelling, field measurements, and laboratory experiments.
Download or read book Studies on the Structure of Turbulence written by Joost Alois Businger and published by . This book was released on 1958 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
