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Data Driven Modeling Of Intermittent Turbulence In The Stably Stratified Atmospheric Boundary Layer
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Book Synopsis Data-driven Modeling of Intermittent Turbulence in the Stably Stratified Atmospheric Boundary Layer by : Vyacheslav Boyko
Download or read book Data-driven Modeling of Intermittent Turbulence in the Stably Stratified Atmospheric Boundary Layer written by Vyacheslav Boyko and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analyses of Turbulence in the Neutrally and Stably Stratified Planetary Boundary Layer by : Cedrick Ansorge
Download or read book Analyses of Turbulence in the Neutrally and Stably Stratified Planetary Boundary Layer written by Cedrick Ansorge and published by Springer. This book was released on 2016-09-15 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a study of strong stratification and turbulence collapse in the planetary boundary layer, opening a new avenue in this field. It is the first work to study all regimes of stratified turbulence in a unified simulation framework without a break in the paradigms for representation of turbulence. To date, advances in our understanding and the parameterization of turbulence in the stable boundary layer have been hampered by difficulties simulating the strongly stratified regime, and the analysis has primarily been based on field measurements. The content presented here changes that paradigm by demonstrating the ability of direct numerical simulation to address this problem, and by doing so to remove the uncertainty of turbulence models from the analysis. Employing a stably stratified Ekman layer as a simplified physical model of the stable boundary layer, the three stratification regimes observed in nature— weakly, intermediately and strongly stratified—are reproduced, and the data is subsequently used to answer key, long-standing questions. The main part of the book is organized in three sections, namely a comprehensive introduction, numerics, and physics. The thesis ends with a clear and concise conclusion that distills specific implications for the study of the stable boundary layer. This structure emphasizes the physical results, but at the same time gives relevance to the technical aspects of numerical schemes and post-processing tools. The selection of the relevant literature during the introduction, and its use along the work appropriately combines literature from two research communities: fluid dynamics, and boundary-layer meteorology.
Book Synopsis An Examination of Structure and Parameterization of Turbulence in the Stably-stratified Atmospheric Boundary Layer by : Paul Harold Ruscher
Download or read book An Examination of Structure and Parameterization of Turbulence in the Stably-stratified Atmospheric Boundary Layer written by Paul Harold Ruscher and published by . This book was released on 1987 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The very stable boundary layer is a region of the atmosphere typified by large vertical gradients of temperature and momentum. Analysis of very stable atmospheric flows is complicated by the presence of nonlinear interactions among gravity waves, shear-driven overturning circulations, two-dimensional vortical modes and intermittent turbulence in various stages of development. This study examines the horizontal structure of a very stable atmospheric boundary layer, using data obtained primarily from terrain-following aircraft flights over central Oklahoma. Several diagnostic procedures are applied to the aircraft data, including classical and rotary spectral analysis, principal component analysis, and structure functions. Coherent structures with sharp boundaries are examined with a new conditional sampling technique which requires little a priori specification of sampling criteria. Because the flows involve sharp boundaries, spectral techniques do not provide as much useful information as other more localized procedures. The edges of the coherent structures are regions of significant vertical heat transport, a feature not often emphasized in studies of gravity waves and vortical modes in the stable boundary layer. The presence of significant turbulence even for large stability has implications for modelling of the very stable boundary layer. Forecasts of minimum temperature, boundary layer height, inversion characteristics, and pollutant dispersal are all significantly affected by turbulent mixing. Many models of the stable boundary layer artificially arrest the mixing under stable conditions, resulting in, for example, overestimates of nocturnal cooling. A new parameterization of the stable boundary layer is studied here by incorporating it into an existing model of the planetary boundary layer. The model is then run with one-dimensional sensitivity tests for an idealized atmosphere and with data from Wangara day 33. A simulation over snow cover is also examined. The tests substantiate the role of vertical mixing in ameliorating nocturnal cooling. An additional improvement is a more realistic boundary layer height for moderate wind speeds.
Book Synopsis Improved Parameterization of Stably Stratified Boundary Layer Turbulence in Atmospheric Models by :
Download or read book Improved Parameterization of Stably Stratified Boundary Layer Turbulence in Atmospheric Models written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the course of the project, our research has spanned over several areas encompassing theoretical, numerical and phenomenological aspects of stably stratified atmospheric boundary layers (SBLs). We have laid a solid foundation for studying stably stratified turbulence in the framework of a Quasi-Normal Scale Elimination theory (QNSE) developed by us. We consider the QNSE theory as a major breakthrough in this field. Being maximally proximate to the first principles, the theory penetrates very deeply into the physics of anisotropic turbulence and turbulence-wave interaction yet its calculations can be carried out analytically almost to the final results. We have performed initial analytical exploration of the new theory and implemented it in Reynolds-averaged, Navier-Stokes (RANS) models whose predictions agree well with data collected in BASE and SHEBA campaigns. In addition, we investigated non-local features of stable planetary boundary layers (PBLs) caused by semi-organized structures overlooked in traditional boundary-layer meteorology and in PBL schemes currently used in atmospheric models. Theoretical developments focused on basic length scales characterizing semi-organized structures and corresponding revision of classical similarity theory, PBL depth equations, and bulk resistance and heat/mass transfers laws.
Book Synopsis A Study of Turbulence in an Evolving Stable Atmospheric Boundary Layer Using Large-eddy Simulation by :
Download or read book A Study of Turbulence in an Evolving Stable Atmospheric Boundary Layer Using Large-eddy Simulation written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A study is made of the effects of stable stratification on the fine-scale features of the flow in an evolving stable boundary layer (SBL). Large-eddy simulation (LES) techniques are used so that spatially and temporally varying and intermittent features of the turbulence can be resolved; traditional Reynolds-averaging approaches are not well suited to this. The LES model employs a subgrid turbulence model that allows upscale energy transfer (backscatter) and incorporates the effects of buoyancy. The afternoon, evening transition, and nighttime periods are simulated. Highly anisotropic turbulence is found in the developed SBL, with occasional periods of enhanced turbulence. Energy backscatter occurs in a fashion similar to that found in DNS, and is an important capability in LES of the SBL. Coherent structures are dominant in the SBL, as the damping of turbulent energy occurs more at the smaller, less organized scales.
Book Synopsis Atmospheric Boundary Layers by : Alexander Baklanov
Download or read book Atmospheric Boundary Layers written by Alexander Baklanov and published by Springer Science & Business Media. This book was released on 2007-10-30 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents peer-reviewed papers from the NATO Advanced Research Workshop on Atmospheric Boundary Layers held in April 2006. The papers are divided into thematic sessions: nature and theory of turbulent boundary layers; boundary-layer flows: modeling and applications to environmental security; nature, theory and modeling of boundary-layer flows; air flows within and above urban and other complex canopies: air-sea-ice interaction.
Book Synopsis The Atmospheric Boundary Layer by : J. R. Garratt
Download or read book The Atmospheric Boundary Layer written by J. R. Garratt and published by Cambridge University Press. This book was released on 1994-04-21 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives a comprehensive and lucid account of the science of the atmospheric boundary layer (ABL). There is an emphasis on the application of the ABL to numerical modelling of the climate. The book comprises nine chapters, several appendices (data tables, information sources, physical constants) and an extensive reference list. Chapter 1 serves as an introduction, with chapters 2 and 3 dealing with the development of mean and turbulence equations, and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modelling of the ABL is crucially dependent for its realism on the surface boundary conditions, and chapters 4 and 5 deal with aerodynamic and energy considerations, with attention to both dry and wet land surfaces and sea. The structure of the clear-sky, thermally stratified ABL is treated in chapter 6, including the convective and stable cases over homogeneous land, the marine ABL and the internal boundary layer at the coastline. Chapter 7 then extends the discussion to the cloudy ABL. This is seen as particularly relevant, since the extensive stratocumulus regions over the subtropical oceans and stratus regions over the Arctic are now identified as key players in the climate system. Finally, chapters 8 and 9 bring much of the book's material together in a discussion of appropriate ABL and surface parameterization schemes in general circulation models of the atmosphere that are being used for climate simulation.
Book Synopsis A Parameterization of Intermittent Turbulence in the Stable Boundary Layer by :
Download or read book A Parameterization of Intermittent Turbulence in the Stable Boundary Layer written by and published by . This book was released on 2003 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric boundary layer is of special interest due to its direct impact and interaction with the surface of the earth where most human activity occurs. The daytime boundary layer is dominated by convective turbulence, and thus is modeled easily. However, sources of turbulence at night are multiple and varied, making the flow more difficult to predict. And yet it is important to predict nocturnal dynamics because of its influences on aviation, the dispersion of pollutants, and fog formation.
Book Synopsis Turbulence in the Atmosphere by : John C. Wyngaard
Download or read book Turbulence in the Atmosphere written by John C. Wyngaard and published by Cambridge University Press. This book was released on 2018-03-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on his over forty years of research and teaching, John C. Wyngaard's textbook is an excellent up-to-date introduction to turbulence in the atmosphere and in engineering flows for advanced students, and a reference work for researchers in the atmospheric sciences. Part I introduces the concepts and equations of turbulence. It includes a rigorous introduction to the principal types of numerical modeling of turbulent flows. Part II describes turbulence in the atmospheric boundary layer. Part III covers the foundations of the statistical representation of turbulence and includes illustrative examples of stochastic problems that can be solved analytically. The book treats atmospheric and engineering turbulence in a unified way, gives clear explanation of the fundamental concepts of modeling turbulence, and has an up-to-date treatment of turbulence in the atmospheric boundary layer. Student exercises are included at the ends of chapters, and worked solutions are available online for use by course instructors.
Book Synopsis Practical Meteorology by : Roland Stull
Download or read book Practical Meteorology written by Roland Stull and published by Sundog Publishing, LLC. This book was released on 2018 with total page 942 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantitative introduction to atmospheric science for students and professionals who want to understand and apply basic meteorological concepts but who are not ready for calculus.
Book Synopsis The Atmospheric Sciences by : National Research Council
Download or read book The Atmospheric Sciences written by National Research Council and published by National Academies Press. This book was released on 1998-11-22 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technology has propelled the atmospheric sciences from a fledgling discipline to a global enterprise. Findings in this field shape a broad spectrum of decisionsâ€"what to wear outdoors, whether aircraft should fly, how to deal with the issue of climate change, and more. This book presents a comprehensive assessment of the atmospheric sciences and offers a vision for the future and a range of recommendations for federal authorities, the scientific community, and education administrators. How does atmospheric science contribute to national well-being? In the context of this question, the panel identifies imperatives in scientific observation, recommends directions for modeling and forecasting research, and examines management issues, including the growing problem of weather data availability. Five subdisciplinesâ€"physics, chemistry, dynamics and weather forecasting, upper atmosphere and near-earth space physics, climate and climate changeâ€"and their status as the science enters the twenty-first century are examined in detail, including recommendations for research. This readable book will be of interest to public-sector policy framers and private-sector decisionmakers as well as researchers, educators, and students in the atmospheric sciences.
Book Synopsis An Introduction to Boundary Layer Meteorology by : Roland B. Stull
Download or read book An Introduction to Boundary Layer Meteorology written by Roland B. Stull and published by Springer Science & Business Media. This book was released on 1988-07-31 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Part of the excitement in boundary-layer meteorology is the challenge associated with turbulent flow - one of the unsolved problems in classical physics. An additional attraction of the filed is the rich diversity of topics and research methods that are collected under the umbrella-term of boundary-layer meteorology. The flavor of the challenges and the excitement associated with the study of the atmospheric boundary layer are captured in this textbook. Fundamental concepts and mathematics are presented prior to their use, physical interpretations of the terms in equations are given, sample data are shown, examples are solved, and exercises are included. The work should also be considered as a major reference and as a review of the literature, since it includes tables of parameterizatlons, procedures, filed experiments, useful constants, and graphs of various phenomena under a variety of conditions. It is assumed that the work will be used at the beginning graduate level for students with an undergraduate background in meteorology, but the author envisions, and has catered for, a heterogeneity in the background and experience of his readers.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Conceptual Boundary Layer Meteorology by : April L. Hiscox
Download or read book Conceptual Boundary Layer Meteorology written by April L. Hiscox and published by Academic Press. This book was released on 2022-08-27 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conceptual Boundary Layer Meteorology: The Air Near Here explains essential boundary layer concepts in a way that is accessible to a wide number of people studying and working in the environmental sciences. It begins with chapters designed to present the language of the boundary layer and the key concepts of mass, momentum exchanges, and the role of turbulence. The book then moves to focusing on specific environments, uses, and problems facing science with respect to the boundary layer. Uses authentic examples to give readers the ability to utilize real world data Covers boundary layer meteorology without requiring knowledge of advanced mathematics Provides a set of tools that can be used by the reader to better understand land-air interactions Provides specific applications for a wide spectrum of environmental systems
Book Synopsis The Atmosphere and Climate of Mars by : Robert M. Haberle
Download or read book The Atmosphere and Climate of Mars written by Robert M. Haberle and published by Cambridge University Press. This book was released on 2017-06-29 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humanity has long been fascinated by the planet Mars. Was its climate ever conducive to life? What is the atmosphere like today and why did it change so dramatically over time? Eleven spacecraft have successfully flown to Mars since the Viking mission of the 1970s and early 1980s. These orbiters, landers and rovers have generated vast amounts of data that now span a Martian decade (roughly eighteen years). This new volume brings together the many new ideas about the atmosphere and climate system that have emerged, including the complex interplay of the volatile and dust cycles, the atmosphere-surface interactions that connect them over time, and the diversity of the planet's environment and its complex history. Including tutorials and explanations of complicated ideas, students, researchers and non-specialists alike are able to use this resource to gain a thorough and up-to-date understanding of this most Earth-like of planetary neighbours.
Book Synopsis Modeling Complex Turbulent Flows by : Manuel D. Salas
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.
Book Synopsis Data-driven Approach for Turbulence Modeling in Rotating Flows and Stratified Flows by : Xinyi Huang
Download or read book Data-driven Approach for Turbulence Modeling in Rotating Flows and Stratified Flows written by Xinyi Huang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence modeling, including wall models in large-eddy simulations (LESs) and RANS models in Reynolds-averaged Navier-Stokes (RANS) simulations, is usually not considered for non-canonical flows, including rotating flows and stratified flows. Modeling non-canonical flows encounters difficulties. Some of the main difficulties lie in the fact that these flows have multiple flow controlling parameters (FCPs), and thus, the flow behavior is hard to explore, let alone get accurate modeling. The data-driven approach is considered a possible solution to this. The increasing computational resources and shared turbulence data allow another way to utilize the data other than pure human analyses of the physics. However, pure data-driven methods are often criticized for their weak interpretability and generalizability. In this work, multiple data-driven techniques are applied to some persistent problems in turbulence modeling under the circumstances of rotating flows and stratified flows. The problems include not only the accurate modeling of the flow but also the efficient FCP space exploration, model selection, uncertainty quantification, etc. Both the dataset and existing knowledge of physics are utilized, and then data-driven approach shows the interpretability and generalizability. They show how these traditionally difficult problems can be tackled through physics-informed data-driven approach, which significantly saves human labor. To be more specific, data-driven approach to wall modeling is compared to physics-based approach for a spanwise rotating channel, and it shows a more accurate yet still generalizable behavior. When modeling is extended to an arbitrarily directional rotating channel, a surrogate model is efficiently developed through the utilization of Bayesian optimization, when such behavior is never understood in the existing literature. Data-driven approach is also applied to RANS modeling. The diverse modeling makes model selection awkward for a newbie, and we train a recommender system to provide guidelines. Modeling itself for non-canonical cases, e.g., stratified flows, is also troublesome, because the multi-stage behavior of the flow requires automated switching of modeling between different models as the flow develops. A linear logistic regression is developed for automating the classification. The models can then be evaluated through a global epistemic uncertainty quantification (UQ) method, which allows the exploration of dominating terms in a RANS model and determining a priori if a calibration can generalize to other flow conditions. In general, data-driven approach has been used for multiple applications in turbulence modeling, and they show their capability and interpretability.
