Download or read book Some Spectra of Turbulence in the Free Atmosphere written by Aaron Fleisher and published by . This book was released on 1957 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The average rate at which the radar signal crosses a voltage level is linearly dependent on the root mean square of the turbulent wind component in the direction of the beam (1, 2), and therefore constitutes an anemometer with these characteristics. All tracers within the illuminated volume contribute to the signal. This anemometer therefore senses an average over the space they occupy which is at most equivalent to a cylinder standing half a pulse length high and straddling a diameter equal to the product of the range and beamwidth.
Download or read book On the Spectra of Turbulence in the Free Atmosphere written by John D. Stackpole and published by . This book was released on 1959 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence in the Free Atmosphere written by N. Vinnichenko and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence-the randomly disordered movement of volumes of air of widely varying size-is one of the characteristic features of atmospheric air flows; its investigation is essential for the solution of several theoretical and practical problems. Until recently, owing to experimental difficulties, research on turbu lence was confmed mainly to the lower half of the troposphere. Theoretical investigations have consequently been based on these data. The rapid development of high-altitude aviation and cases of aircraft encoun tering hazardous turbulence led to a sharp intensification of research on turbu lence in the atmosphere up to 10-12 km, and subsequently at greater altitudes. Such research was confined initially to the characterization of the frequency of occurrence of gusts of different speeds, their relation to altitude, geographical conditions, time of day and year, and so on. At the end of the fifties, when the required measuring equipment and experimental techniques had been developed, it became possible to investigate the complete statistical characteristics of turbu lence: the spectral densities of the velocity fluctuations of air flows, structure functions, etc. These data stimulated the further development of theory related to the specific conditions of the free atmosphere.
Download or read book Kolmogorov Spectra of Turbulence I written by Vladimir E. Zakharov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the human organism is itself an open system, we are naturally curious about the behavior of other open systems with fluxes of matter, energy or information. Of the possible open systems, it is those endowed with many degrees of freedom and strongly deviating from equilibrium that are most challenging. A simple but very significant example of such a system is given by developed turbulence in a continuous medium, where we can discern astonishing features of universality. This two-volume monograph deals with the theory of turbulence viewed as a general physical phenomenon. In addition to vortex hydrodynamic turbulence, it considers various cases of wave turbulence in plasmas, magnets, atmosphere, ocean and space. A sound basis for discussion is provided by the concept of cascade turbulence with relay energy transfer over different scales and modes. We shall show how the initial cascade hypothesis turns into an elegant theory yielding the Kolmogorov spectra of turbulence as exact solutions. We shall describe the further development of the theory discussing stability prob lems and modes of Kolmogorov spectra formation, as well as their matching with sources and sinks. This volume is dedicated to developed wave turbulence in different media.
Download or read book Turbulence in the Free Atmosphere written by N. K. Vinnichenko and published by . This book was released on 1980 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence-the randomly disordered movement of volumes of air of widely varying size-is one of the characteristic features of atmospheric air flows; its investigation is essential for the solution of several theoretical and practical problems. Until recently, owing to experimental difficulties, research on turbu lence was confmed mainly to the lower half of the troposphere. Theoretical investigations have consequently been based on these data. The rapid development of high-altitude aviation and cases of aircraft encoun tering hazardous turbulence led to a sharp intensification of research on turbu lence in the atmosphere up to 10-12 km, and subsequently at greater altitudes. Such research was confined initially to the characterization of the frequency of occurrence of gusts of different speeds, their relation to altitude, geographical conditions, time of day and year, and so on. At the end of the fifties, when the required measuring equipment and experimental techniques had been developed, it became possible to investigate the complete statistical characteristics of turbu lence: the spectral densities of the velocity fluctuations of air flows, structure functions, etc. These data stimulated the further development of theory related to the specific conditions of the free atmosphere.
Download or read book Radar Measurement of the Spectra of Turbulence in the Free Atmosphere written by John D. Stackpole and published by . This book was released on 1959 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Relative motion of precipitation particles causes fluctuations in a radar signal reflected from a number of such scatterers. These fluctuations contain information about the wind structure in the volume sampled by the radar since the wind causes the relative motions. The output of the R-meter, a device which measures the rate at which the fluctuating signal crosses a specified voltage level, measures the standard deviation of the relative gust velocity distribution within the sampled volume and, as such, is a measure of the intensity of the turbulence. Hannonic analysis of the R-meter record reveals that the turbulent intensity at various altitudes from 600 feet to 18,000 feet varies periodically with a frequency near 0.005 cps. The shape of the turbulence spectra are compared with the theoretical shape predicted by the Kolmogoroff theory of turbulent energy decay but no significant agreement is found. The location of the spectral maxima, combined with measurements of the wind, gives evidence that the rainy atmosphere is composed of an array of relatively more and less turbulent regions transported with the wind. The dimensions of the array are seen to be on the order of 11,000 feet in agreement with measured convective cell sizes, which implies that they may well be caused by convective processes present even in stratiform rain.
Download or read book Turbulence in the Atmosphere written by John C. Wyngaard and published by Cambridge University Press. This book was released on 2010-01-28 with total page 407 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.
Download or read book Some Examples of the Energy Spectrum of Turbulence in the Atmosphere Near the Ground written by G.D. Robinson and published by . This book was released on 1953 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spectral Structure of Turbulence in a Free Atmosphere Based on Data Obtained by Aircraft written by G. N. Shur and published by . This book was released on 1966 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: On the basis of the analysis of experimental data on turbulence obtained by a TU-104 aircraft, this article examines the energy spectrum of the vertical velocity component of turbulent gusts in a temperature-stratified atmosphere. The relationship between the spectra of the vertical and horizontal component in a stably stratified atmosphere is also examined. The measurements of the gust loads in a narrow band of frequencies (wave numbers) make it possible to obtain the dispersions in the velocities of gusts in a wide range of scales.
Download or read book Longitudinal and Lateral Spectra of Turbulence in the Atmospheric Boundary Layer written by George H. Fichtl and published by . This book was released on 1970 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Related Phenomena written by Regis Barille and published by BoD – Books on Demand. This book was released on 2019-04-17 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents some of the most important results concerning atmospheric turbulence and some of its effects on the propagation of a light beam. Atmospheric turbulence causes fluctuations in both the intensity and the phase of the beam and still must be understood and modelized for applications in photonics or environmental metrology. The future of free-space optical (FSO) communication through atmospheric turbulence channels is especially of interest and research on high bit-rate communications attracts more and more interest as an alternative to radio links because of bandwidth, spectrum, and security issues. Some of the current solutions for improving FSO communications are presented in this book.
Download or read book Spectra of Internal Waves and Turbulence in Stratified Fluids Part I General Discussion and Indications from Measurements in Stably Stratified Atmosphere and Ocean written by Yih-Ho Pao and published by . This book was released on 1969 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unified spectral description of internal waves and turbulence in stably stratified atmosphere and ocean is proposed. We envisage that the fluctuating motions in a free atmosphere with scales smaller than the synoptic scale consist of internal waves and turbulence. At low wavenumbers, internal waves predominate; this range of wavenumbers may be called the internal wave subrange. The internal waves can be identified from the characteristics of velocity-scalar co-spectra and quadrature-spectra, as shown recently by Pao in a laboratory experiment. When the internal waves are sufficiently strong and distinct, the different harmonics of internal waves may present themselves in the auto-spectra of velocity and temperature, where the peaks and valleys are clearly identifiable. This, we believe, explains the presence of peaks and valleys in some velocity auto-spectra of clear air turbulence measured in strongly stratified regions of the atmosphere. At intermediate wavenumbers (buoyant subrange), the buoyancy effect is still strong but the turbulent scrambling process becomes important; the higher-order harmonics of internal waves are no longer distinct and cannnot be detected in the auto-spectra. (Author).
Download or read book The Transport of Energy Over the Turbulence Spectrum of the Free Atmosphere written by G. N. Shur and published by . This book was released on 1972 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are shown of experimental studies of the turbulence spectrum in the free atmosphere performed on specially equipped aircraft. In analyzing the data, it is assumed that the energy flow in the spectrum is directed toward large wave numbers. It is shown that the rate of energy transport over the spectrum in a certain wave number range depends on the thermal stratification. Curves are presented which characterize the rate of energy transport over the spectrum in the buoyance subrange. These curves are not continuous, but are localized in a narrow wave number band. (Author).
Download or read book Coherent Doppler Wind Lidars in a Turbulent Atmosphere written by Viktor Banakh and published by Artech House. This book was released on 2013-09-01 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiophysical tools for measuring atmospheric dynamics include sodars, Doppler radars, and Doppler lidars. Among these, coherent Doppler lidars (CDLs) have been considered the best for remote measurement of wind turbulence. This is important not only for understanding the exchange processes in the boundary layer, but also in the applied aspect, such as aviation safety. CDLs significantly extend possibilities of experimental investigation of not only wind turbulence, but also coherent structures such as aircraft wake vortices. The authors of this book conducted field tests of the developed methods of lidar measurements of the wind velocity, atmospheric turbulence parameters, and aircraft wake vortices. This valuable resource, containing over 500 equations based on original results from the authors’ work, gives professionals a comprehensive description of the operating principles of continuous wave and pulsed coherent Doppler lidars. This book studies the possibilities of obtaining information about wind turbulence from data measured by continuous wave and pulsed CDLs. The procedures for estimation are described, as well as algorithms for numerical simulation. Results on the vortex behavior and evolution are then presented.
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 262 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 1994 with total page 392 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 1972 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
