Download or read book The Aeronautical Journal written by and published by . This book was released on 1989 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spanwise Measurements of Vertical Components of Atmospheric Turbulence written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Correlation and spectrum magnitude estimates are computed for vertical gust velocity measurements at the nose and wing tips of a NASA B-57B aircraft for six level flight, low speed and low altitude runs and are compared with those of the von Karman atmospheric turbulence model extended for spanwise relationships. The distance between the wing tips was 62.6 ft. Airspeeds ranged from about 330 to 400 ft/sec, heights above the ground ranged from near ground level to about 5250 ft. and gust velocity standard deviations ranged from 4.10 to 8.86 ft/sec. Integral scale lengths, determined by matching measured autocorrelation estimates with those of the model, ranged from 410 to 2050 ft. Digital signals derived from piezoelectric sensors provided continuous pressure and airspeed measurements. Some directional acceleration sensitivity of the sensors was eliminated by sensor orientation, and their performance was spectrally verified for the higher frequencies with supplemental onboard piezoresistive sensors. The model appeared to satisfactorily predict the trends of the measured cross-correlations and cross-spectrum magnitudes, particularly between the nose and wing tips. However, the measured magnitude estimates of the cross-spectra between the wing tips exceeded the predicted levels at the higher frequencies. Causes for the additional power across the wing tips were investigated. Vertical gust velocity components evaluated along and lateral to the flight path implied that the frozen-turbulence-field assumption is a suitable approximation. Sleeper, Robert K. Langley Research Center...
Download or read book Spanwise Measurements of Vertical Components of Atmospheric Turbulence written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Correlation and spectrum magnitude estimates are computed for vertical gust velocity measurements at the nose and wing tips of a NASA B-57B aircraft for six level flight, low speed and low altitude runs and are compared with those of the von Karman atmospheric turbulence model extended for spanwise relationships. The distance between the wing tips was 62.6 ft. Airspeeds ranged from about 330 to 400 ft/sec, heights above the ground ranged from near ground level to about 5250 ft. and gust velocity standard deviations ranged from 4.10 to 8.86 ft/sec. Integral scale lengths, determined by matching measured autocorrelation estimates with those of the model, ranged from 410 to 2050 ft. Digital signals derived from piezoelectric sensors provided continuous pressure and airspeed measurements. Some directional acceleration sensitivity of the sensors was eliminated by sensor orientation, and their performance was spectrally verified for the higher frequencies with supplemental onboard piezoresistive sensors. The model appeared to satisfactorily predict the trends of the measured cross-correlations and cross-spectrum magnitudes, particularly between the nose and wing tips. However, the measured magnitude estimates of the cross-spectra between the wing tips exceeded the predicted levels at the higher frequencies. Causes for the additional power across the wing tips were investigated. Vertical gust velocity components evaluated along and lateral to the flight path implied that the frozen-turbulence-field assumption is a suitable approximation. Sleeper, Robert K. Langley Research Center...
Download or read book Evaluation of Effects of High altitude Turbulence Encounters on the XB 70 Airplane written by Ronald J. Wilson and published by . This book was released on 1971 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Turbulence in the Free Atmosphere written by N. Vinnichenko and published by Springer. This book was released on 1980-08 with total page 334 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 Aviation Turbulence written by Robert Sharman and published by Springer. This book was released on 2016-06-27 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anyone who has experienced turbulence in flight knows that it is usually not pleasant, and may wonder why this is so difficult to avoid. The book includes papers by various aviation turbulence researchers and provides background into the nature and causes of atmospheric turbulence that affect aircraft motion, and contains surveys of the latest techniques for remote and in situ sensing and forecasting of the turbulence phenomenon. It provides updates on the state-of-the-art research since earlier studies in the 1960s on clear-air turbulence, explains recent new understanding into turbulence generation by thunderstorms, and summarizes future challenges in turbulence prediction and avoidance.
Download or read book Low Altitude Wind Shear and Its Hazard to Aviation written by National Research Council and published by National Academies Press. This book was released on 1983-02-01 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
