Download or read book A Technique for Analyzing the Structure of Atmospheric Turbulence written by T. C. Kerrigan and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technique for Analyzing the Structure of Atmospheric Turbulence written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique to assess the contribution of large scale coherent gust structures to the statistical properties of atmospheric turbulence is discussed. First, an orthonormal family of functions is constructed in terms of which the history of sample paths for a stationary wind process can be analyzed. Next, expressing the state of the wind in terms of the expansion coefficients makes it possible to approximate the wind process by a Markov process. A technique is then developed for estimating the Markov transition probability based on actual wind data. Finally, the form of this transition probability represents an analysis of the gust structure implicit in the wind data.
Download or read book Wavelet Analysis of Atmospheric Turbulence Structures written by and published by . This book was released on 1995 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors examined three specific methods for using the wavelet transform to derive information on the turbulence structure in the atmospheric boundary layer from raw data. The scale-time cross section method yields a qualitative picture of turbulence structures occurring at different times and different scales, the wavelet variance method provides a relatively objective estimate of principal scales associated with organized structures, and the wavelet cross correlation helps in identifying motions that are most important in turbulent transport and spatial coherence. The wavelet analysis can also be used to decompose the data for different scales and to detect coherent structures objectively by using the transform coefficient at the principal scale detected by the variance method (Collineau and Brunet, 1993; Coulter and Li, 1995). These methods can improve their capability to unfold the data for hidden information that is difficult to obtain from traditional spectral analysis and thus can provide a useful tool for understanding multiscale phenomena in the atmospheric boundary layer.
Download or read book Gust Structure and Gust Statistics Results from an Analysis of Atmospheric Turbulence Measurements by Using Conditional Sampling Technique written by Magnus Linde and published by . This book was released on 1983 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Air Turbulence and its Methods of Detection written by Leonardo Di G. Sigalotti and published by CRC Press. This book was released on 2023-02-24 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a concise guide dealing with the subject of air turbulence and its methods of detection with particular applications to aviation turbulence. It begins with a general description of turbulence and provides a background into the nature and causes of atmospheric turbulence that affect aircraft motion, giving updates on the state-of-the-art research on clear air turbulence (CAT). Important physical processes leading to the Kelvin-Helmholtz instability, a primary producer of CAT, are also explained. The several categories of CAT along with its impact on commercial aviation are also presented in a separate chapter, with particular emphasis on the structural damages to planes and injuries. The central theme of the book deals with both the earlier and the latest CAT detecting methods and techniques for remote and in situ sensing and forecasting. A concise presentation of new technologies for reducing aviation weather-related accidents is also offered. A chapter on the weather accident prevention project of the NASA aviation safety program is also included. Additionally, the book ends with a full description of the recent research activities on CAT and future challenges in turbulence detection, prediction and avoidance.
Download or read book The Structure of Atmospheric Turbulence written by John Leask Lumley and published by . This book was released on 1964 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Diffusion in the Atmosphere written by Alfred K. Blackadar and published by Springer. This book was released on 2012-12-06 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book grew out of an introductory course that I was invited to teach on a number of occasions to senior and graduate level students at the University of Kid. I have cherished these opportunities in part because I was never required to conduct examinations or give grades. For the students, however, my good fortune presented special problems that induced my sympathy: in addition to having to contend with a foreign language, they would eventually have to confront an examiner with his own ideas about what they should have learned. Although I always left a copy of my lecture notes with this person, they were too sketchy to be of much use. The present book is an attempt to solve some of these problems. The content is intended to be as broad as possible within the limitations of an introductory one-semester course. It aims at providing an insightful view of present understanding, emphasizing the methods and the history of their development. In particular I have tried to expose the power of intuitive reasoning - the nature of tensor invariants, the usefulness of dimensional analysis, and the relevance of scales of physical quantities in the inference of relationships. I know of no other subject that has benefited more from these important tools, which seem to be widely neglected in the teaching of more fundamental disciplines.
Download or read book Novel Methods for the Quantification of Atmospheric Turbulence Strength in the Atmospheric Surface Layer written by Raymond James Oermann and published by . This book was released on 2014 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric turbulence is a random and chaotic process brought about by energy transport mechanisms in the atmosphere. Of particular focus in this research program is the energy transport occurring in the atmospheric surface layer between ground heated air parcels and the air directly above. This dynamic process is impacted by so many apparently random initial conditions and boundary states that a precise analytical description of the process is beyond current computation. The process of turbulence can, however, be statistically analysed and characterised empirically. Observable phenomena such as scintillation have been found to have a range dependence and even the micro-meteorological structure of the turbulent eddies (chiefly responsible for the convective energy transport) have had their spatial distribution, scale size and power spectra examined in detail. As complex as the field is, one is left in no doubt, when viewing a scene through strong turbulence, that this dynamic and random process disrupts and perturbs the passage of visible radiation and is seen to severely degrade the quality of imagery. So the question raised is: "How can the strength of atmospheric turbulence be determined from either physical measurements of meteorological data or from sequences of perturbed imagery?" In order for imagery to be corrected for turbulence-induced degradation, or even the reliability of the imagery for uses such as object recognition and identification, an accurate measure of the current turbulence strength is required. After exploring the turbulence phenomenon and its impact upon laser spots and imagery, three parallel approaches to the determination of the current turbulence strength were pursued in this research program. The first was a controlled laboratory experiment where an artificial turbulent air- stream generated above a hot plate was investigated. Using sensitive temperature probes the temperature structure function (a quantity specifically developed to describe the spatial nature of a turbulent field) in a region of relatively high turbulence strength was determined. The homogeneity and isotropy of this turbulent space was then assessed. The instrument and processes developed were also applied in the field to studies of an ambient turbulent field. Measurements of turbulence strength made in this way were compared to results from a commercial scintillometer. The second line of research was field based. It involved the assessment of a range of observable features of the effects of turbulent air masses upon visible imagery. These features included analysis of the apparent motion of an incoherent light source and features of the scene. These observable effects were assessed along a horizontal path 1.5 m above the ground for their ability to infer the strength of the turbulent air mass through which the radiation had passed. The third line of research involved the development of an understanding of the impact of specific local meteorological parameters on the strength of turbulence. A major outcome from over one hundred days of data was the development of an empirical model of turbulence strength that improves upon previous models from the literature. The merits and shortcomings of each of these approaches to the characterisation of atmospheric turbulence conditions are compared. Ultimately, the ability to use imagery sequences acquired through turbulence, the temperature structure function of a sample volume or an empirical model using meteorological parameters to determine the strength of that turbulence, were assessed. This information is a necessary first step in the development of techniques for the mitigation of turbulence-induced, image distortion.
Download or read book The Structure of Atmospheric Turbulence written by John Leask Lumley and published by . This book was released on 1964 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding the Effect of Atmospheric Turbulence on Optical and Infrared Propagation Using Hilbert Phase Analysis written by and published by . This book was released on 2007 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The refractive index structure parameter C(2/n) is a figure of merit used to describe the magnitude of the effect of turbulence in the atmosphere. Understanding the influence of different local climate parameters upon C(2/n) is an important step toward developing a prediction model for in-field laser interrogators. The layered structure of the atmosphere and its random behavior present unique challenges to theoretical and experimental studies in propagation research. This article presents a novel technique termed Hilbert Phase Analysis (HPA) to provide insights into the physical interactions. We explore the technique's use in analyzing the dependence of C(2/n) on local climate variables using data recently obtained from campaigns conducted in Puerto Rico.
Download or read book International Symposium on Atmospheric Turbulence in the Boundary Layer written by Edgar Wendell Hewson and published by . This book was released on 1952 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterizing Turbulent Coherent Structures in the Atmospheric Surface Layer Using Integrated Quadrant Analysis written by Mary Rose Mangan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrated quadrant analysis is a novel technique to characterize the trajectory and strength of turbulent coherent structures in the atmospheric surface layer. By integrating the three-dimensional velocity field characterized by traditional quadrant analysis with respect to time, the trajectory history of individual coherent structures can be preserved with Eulerian turbulence measurements. We developed a method to identify the ejection phase of coherent structures based on turbulent kinetic energy (TKE). Identifying coherent structures using TKE preforms better than identifying them with the only streamwise and vertical velocity components because some coherent structures are strongly linked to the cross-stream velocity. By combining this identification method with integrated quadrant analysis, one can animate or plot the trajectory of individual coherent structures. This procedure connects a coherent ejection with the subsequent sweep and quiescent period in time to visualize and quantify the strength and the duration of a coherent structure. We developed and verified the method of integrated quadrant analysis with data from three field studies: the Eclipse Boundary Layer Experiment (EBLE) in Corvallis, OR in August 2017, the Vertical Cherry Array Experiment (VACE) in Linden, CA in November 2019 and the Canopy Horizontal Array Turbulence Study (CHATS) in Dixon, CA in the spring of 2007. Integrated quadrant analysis is a promising addition to traditional turbulence analysis techniques because it provides information about an individual coherent structure that consists of both an ejection and a sweep attached to each other in a single sequence. The integrated analysis also helps to portray an eddy trajectory in three-dimensions around a sensor, which indicates that the turbulent cross-stream velocity is usually an important momentum transport component in a coherent structure. In the VACE and CHATS experiments, there is a plane of preferred eddy trajectory for each individual coherent structure. The plane depends on the component of the double headed hairpin vortex that the sensor measures.
Download or read book Structure of Atmospheric Turbulence in the Surface Layer written by Robert Armstrong Derrickson and published by . This book was released on 1964 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Method for the Measurement and the Statistical Analysis of Atmospheric Turbulence written by Stavros Christas Tavoularis and published by . This book was released on 1974 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Group Kinetic Theory and Modeling of Atmospheric Turbulence written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: A group kinetic method is developed for analyzing eddy transport properties and relaxation to equilibrium. The purpose is to derive the spectral structure of turbulence in incompressible and compressible media. Of particular interest are: direct and inverse cascade, boundary layer turbulence, Rossby wave turbulence, two phase turbulence; compressible turbulence, and soliton turbulence. Soliton turbulence can be found in large scale turbulence, turbulence connected with surface gravity waves and nonlinear propagation of acoustical and optical waves. By letting the pressure gradient represent the elementary interaction among fluid elements and by raising the Navier-Stokes equation to higher dimensionality, the master equation was obtained for the description of the microdynamical state of turbulence. Tchen, C. M. Unspecified Center...
Download or read book Atmospheric Turbulence written by Hans A. Panofsky and published by Wiley-Interscience. This book was released on 1984-02-03 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: New York : Wiley, c1984.
Download or read book Atmospheric Turbulence Simulation Techniques with Application to Flight Analysis written by Show-Tien Wang and published by . This book was released on 1980 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical modeling of atmospheric turbulence is discussed. The statistical properties of atmospheric turbulence, in particular the probability distribution, the spectra, and the coherence are reviewed. Different atmospheric turbulence simulation models are investigated, and appropriate statistical analyses are carried out to verify their validity. The models for simulation are incorporated into a computer model of aircraft flight dynamics. Statistical results of computer simulated landings for an aircraft having characteristics of a DC-8 are reported for the different turbulence simulation techniques. The significance of various degrees of sophistication in the turbulence simulation techniques on the landing performance of the aircraft is discussed.
