[PDF] Analysis Of Predicted Aircraft Wake Vortex Transport And Comparison With Experiment Volume I Wake Vortex Predictive System Study eBook

Author : M. R. Brashears
Publisher :
Page : 249 pages
File Size : 40,35 MB
Release : 1974
Category :
ISBN :

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A unifying wake vortex transport model is developed and applied to a wake vortex predictive system concept. The fundamentals of vortex motion underlying the predictive model are discussed including vortex decay, bursting and instability phenomena. A parametric and sensitivity analysis is presented to establish baseline uncertainties in the algorithm to allow meaningful comparison of predicted and measured vortex tracks. A detailed comparison of predicted vortex tracks with photographic and groundwind vortex data is presented. Excellent agreement between prediction and measurement is shown to exist when sufficient wind data are available. Application of the Pasquill class criteria is shown to be an effective technique to describe the wind profile in the absence of detailed wind data. The effects of wind shear and the Ekman spiral on vortex transport are discussed. It is shown that the combination of wind shear and ground plane may be possible mechanisms underlying vortex tilting and a theoretical explanation is advanced that is somewhat supported by comparison with the experimental data. Finally, recommendations for further vortex data collection in the vicinity of an airport are presented. (Author).

Author : M. R. Brashears
Publisher :
Page : 231 pages
File Size : 19,43 MB
Release : 1974
Category :
ISBN :

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;Contents: Summary of aircraft flybys; Probable stability conditions prevalent during selected NAFEC flybys at Atlantic City, N.J.; Description of output plots of wake vortex transport computer program; Description of input requirements for Lockheed wake vortex tramsport computer program; Summary of line printer output of Lockheed wake vortex transport computer program; Flow charts for Lockheed wake vortex transport computer program; Summary of predicted wake vortex tracks and comparison with experiment; Report of inventions.

Author : National Research Council
Publisher : National Academies Press
Page : 102 pages
File Size : 36,61 MB
Release : 2008-04-27
Category : Science
ISBN : 0309113792

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Without major changes, the current air transportation system will be unable to accommodate the expected increase in demand by 2025. One proposal to address this problem is to use the Global Positioning System to enable aircraft to fly more closely spaced. This approach, however, might be limited by the wake turbulence problem, which can be a safety hazard when smaller aircraft follow relatively larger aircraft too closely. To examine how this potential hazard might be reduced, Congress in 2005 directed NASA to request a study from the NRC to assess the federal wake turbulence R&D program. This book provides a description of the problem, an assessment of the organizational challenges to addressing wake turbulence, an analysis of the technical challenges in wake turbulence, and a proposal for a wake turbulence program plan. A series of recommendations for addressing the wake turbulence challenge are also given.

Author : David K. Rutishauser
Publisher :
Page : 28 pages
File Size : 19,75 MB
Release : 2001
Category : Air traffic control
ISBN :

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An analysis has been performed on data generated from the two most recent field deployments of the Aircraft Wake Vortex Spacing System (AVOSS). The AVOSS provides reduced aircraft spacing criteria for wake vortex avoidance as compared to the FAA spacing applied under Instrument Flight Rules (IFR). Several field deployments culminating in a system demonstration at Dallas Fort Worth (DFW) International Airport in the summer of 2000 were successful in showing a sound operational concept and the system's potential to provide a significant benefit to airport operations. For DFW, a predicted average throughput increase of 6% was observed. This increase implies 6 or 7 more aircraft on the ground in a one-hour period for DFE operations. Several studies of performacne correlations to system configuration options, and system inputs are also reported. The studies focus on the validation performance of the system.

Author : A.S. Ginevsky
Publisher : Springer Science & Business Media
Page : 166 pages
File Size : 10,77 MB
Release : 2009-07-07
Category : Mathematics
ISBN : 3642017606

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Investigation of vortex wakes behind various aircraft, especially behind wide bodied and heavy cargo ones, is of both scientific and practical in terest. The vortex wakes shed from the wing’s trailing edge are long lived and attenuate only atdistances of10–12kmbehindthe wake generating aircraft. The encounter of other aircraft with the vortex wake of a heavy aircraft is open to catastrophic hazards. For example, air refueling is adangerous operationpartly due to thepossibility of the receiver aircraft’s encountering the trailing wake of the tanker aircraft. It is very important to know the behavior of vortex wakes of aircraft during theirtakeoff andlanding operations whenthe wakes canpropagate over the airport’s ground surface and be a serious hazard to other depart ing or arriving aircraft. This knowledge can help in enhancing safety of aircraft’s movements in the terminal areas of congested airports where the threat of vortex encounters limits passenger throughput. Theoreticalinvestigations of aircraft vortex wakes arebeingintensively performedinthe major aviationnations.Usedforthispurpose are various methods for mathematical modeling of turbulent flows: direct numerical simulation based on the Navier–Stokes equations, large eddy simulation using the Navier–Stokes equations in combination with subrigid scale modeling, simulation based on the Reynolds equations closed with a differential turbulence model. These approaches are widely used in works of Russian and other countries’ scientists. It should be emphasized that the experiments in wind tunnels and studies of natural vortex wakes behind heavy and light aircraft in flight experiments are equally important.