Author: H. N. Murrow
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description

Author: Harold N. Murrow
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 176

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Book Description

Author: Harold L. Crane
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 18

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Book Description
A method for obtaining a power spectrum of gust vertical velocity over a wide range of wavelength from simultaneous measurements made in flight has been devised and applied. This method has the advantage of not involvhg the use of airplane transfer functions. A gust vertical velocity spectrum was determined for one meteorological condition for wavelengths from 10 feet to 60,000 feet. The test was conducted at low altitude in clear- turbulence having a root-mean-square intensity of 5 feet per second. At the higher frequencies (shorterwavelengths), the power spectral density varied at a rate which was between the -5/3 power which has been predicted theoretically and the inverse square of the frequency. The spectrum which was obtained tended to flatten out for the longest test wavelengths.The break frequency which provides an indication of the scale of the turbulence occurred at a wavelength of approximately 6,000 feet. The results obtained indicate that the method of obtaining spectra used in this investigation is practicable.

Author: Yih-Ho Pao
Publisher: Springer
ISBN: 1489956158
Category : Technology & Engineering
Languages : en
Pages : 545

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Book Description

Author: Edward V. Ashburn
Publisher:
ISBN:
Category : Atmospheric physics
Languages : en
Pages : 84

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Book Description
The report consists of analysis of measurements made in HICAT flight program and described in reports issued in 1967 and 1968. Clear air turbulent regions in the altitude range 45,000 to 65,000 ft. varied in length from 1 to 115 nm. Power spectral density curves computed from data from the longer turbulent regions had slopes and scale lengths that varied over a relatively wide range. Composite spectra for altitude and topographic categories for the long turbulent regions had slopes of -1.25 to -1.55 for the vertical component, -1.50 to -1.70 for the lateral component, and -1.45 to -1.60 for the longitudinal component. The scale lengths were all above 8,000 ft. The standard deviations of the root-mean-square gust velocities increase significantly with increase in roughness of underlying terrain. The range in values is 0.9 to 3.4 ft/sec. for the vertical component, 1.5 to 4.6 ft/sec for the lateral component and 1.2 to 4.6 ft/sec. for the longitudinal component. There was relatively little change with altitude. The minimum root-mean-square velocity to be considered turbulence varied 0.95 to 3.02 ft/sec. if truncated spectra were used to establish basic definitions of turbulence.

Author: Richard H. Rhyne
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 56

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Author: Canada. National Research Council
Publisher:
ISBN:
Category : Lee waves
Languages : en
Pages : 32

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Author: Anne Burns
Publisher:
ISBN:
Category :
Languages : en
Pages : 27

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Book Description

Author: Ronald J. Wilson
Publisher:
ISBN:
Category : Atmospheric turbulence
Languages : en
Pages : 92

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Book Description
A turbulence response investigation was conducted with the XB-70 airplane. No special turbulence penetration techniques, speeds, or other restrictions were specified for the investigation, nor were any flights made solely to obtain turbulence data. During 79 flights, turbulence was encountered, and recorded on a VGH recorder, 6.2 percent of the total flight distance at supersonic speeds above an altitude of 12,192 meters (40,000 feet). Geographical locations are given for selected turbulence encounters. For 22 flights the airplane was instrumented to measure true gust velocities and the structural acceleration response to turbulence. The turbulence intensities measured were very low in comparison with those measured at high altitudes in other investigations. Acceleration response spectra, frequency response transfer functions, and coherence functions were computed from three turbulence encounters at Mach numbers of 0.88, 1. 59, and 2.35. Results are compared with calculated studies. Frequencies from the vertical and lateral structural modes, dominant in the airplane acceleration responses, were compared with the natural frequencies of the human body in the vertical and lateral directions.

Author: Leonardo Di G. Sigalotti
Publisher: CRC Press
ISBN: 1000844234
Category : Transportation
Languages : en
Pages : 429

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Book Description
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.