Download or read book Skill of an Aircraft Wake vortex Transport and Decay Model Using Weather Prediction and Observation written by Michael Frech and published by . This book was released on 2007 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wake Turbulence written by National Research Council and published by National Academies Press. This book was released on 2008-04-27 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2007 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Predicted Aircraft Wake Vortex Transport and Comparison with Experiment Volume I Wake Vortex Predictive System Study written by M. R. Brashears and published by . This book was released on 1974 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book Wake Vortex Advisory System WakeVAS Concept of Operations written by and published by DIANE Publishing. This book was released on 2003 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Modeling Studies of Wake Vortex Transport and Evolution Within the Planetary Boundary Layer written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental objective of this research is study behavior of aircraft wake vortices within atmospheric boundary layer (ABL) in support of developing the system, Aircraft VOrtex Spacing System (AVOSS), under NASA's Terminal Area Productivity (TAR) program that will control aircraft spacing within the narrow approach corridors of airports. The purpose of the AVOSS system is to increase airport capacity by providing a safe reduction in separation of aircraft compared to the now-existing flight rules. In our first funding period (7 January 19994 - 6 April 1997), we have accomplished extensive model development and validation of ABL simulations. Using the validated model, in our second funding period (7 April 1997 - 6 April 2000) we have investigated the effects of ambient atmospheric turbulence on vortex decay and descent, Crow instability, and wake vortex interaction with the ground. Recognizing the crucial influence of ABL turbulence on wake vortex behavior, we have also developed a software generating vertical profiles of turbulent kinetic energy (TKE) or energy dissipation rate (EDR), which are, in turn, used as input data in the AVOSS prediction algorithms. Lin, Yuh-Lang and Arya, S. Pal and Kaplan, Michael L. and Han, Jongil Langley Research Center NCC1-188
Download or read book Estimation of Wake Vortex Advection and Decay Using Meteorological Sensors and Aircraft Data written by and published by . This book was released on 1993 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lift-generated wake vortices trailing behind an aircraft present a danger to aircraft following the same or nearby path. The degree of hazard to the following aircraft depends on the nature of the wake encountered in its flight path and on the ability of the aircraft to counter its effects. This report describes the current state of understanding of the factors that influence the motion and dissipation of wake vortices. The relationships of these factors to parameters that are measurable through meteorological sensors and from a priori knowledge of the vortex generating aircraft characteristics are discussed as an aid to structuring development plans for the creation of wake vortex advisory products by the Integrated Terminal Weather System (ITWS) and by special wake vortex sensors.
Download or read book A Flight Evaluation of Methods for Predicting Vortex Wake Effects on Trailing Aircraft written by Glenn H. Robinson and published by . This book was released on 1972 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of four current analytical methods for predicting wing vortex strength and decay rate are compared with the results of a flight investigation of the wake characteristics of several large jet transport aircraft. An empirical expression defining the strength and decay rate of wake vortices is developed that best represents most of the flight-test data. However, the expression is not applicable to small aircraft that would be immersed in the vortex wake of large aircraft.
Download or read book Wake Vortex Algorithm Scoring Results written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-12 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report compares the performance of two models of trailing vortex evolution for which interaction with the ground is not a significant factor. One model uses eddy dissipation rate (EDR) and the other uses the kinetic energy of turbulence fluctuations (TKE) to represent the effect of turbulence. In other respects, the models are nearly identical. The models are evaluated by comparing their predictions of circulation decay, vertical descent, and lateral transport to observations for over four hundred cases from Memphis and Dallas/Fort Worth International Airports. These observations were obtained during deployments in support of NASA's Aircraft Vortex Spacing System (AVOSS). The results of the comparisons show that the EDR model usually performs slightly better than the TKE model.Robins, R. E. and Delisi, D. P. and Hinton, David (Technical Monitor)Langley Research CenterALGORITHMS; KINETIC ENERGY; TURBULENCE MODELS; AIRCRAFT APPROACH SPACING; WING TIP VORTICES; AIRCRAFT WAKES; EVALUATION
Download or read book Flow Visualization of the Wake of a Transport Aircraft Model with Lateral control Oscillations written by Frank L. Jordan and published by . This book was released on 1983 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Formation to Decay written by Klaus Huenecke and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Predictive Wake Vortex Transport Model for Terminal Area Wake Vortex Avoidance written by M. R. Brashears and published by . This book was released on 1976 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wake vortex transport program has been expanded to include viscous effects and the influence of initial roll-up, atmospheric turbulence, and wind shear on the persistence and motion of wake vortices in terminal areas. Analysis of wake characteristics has shown that changes in the spanwise loading due to flaps increase the initial sink rate, decrease the separation, and initiates the circulation decay process earlier. Buoyancy due to jet exhaust entrainment and ambient stratification retards vortex spreading and increases descent. Atmospheric turbulence and shear promote a more rapid decay reducing the late-time descent and spread rates of vortices. Vortex tilting has been related to an interaction involving the wind shear, ground plane, and the vorticity detrainment process. Recognition of the effects of tilting, spanwise loading, vorticity detrainment, burst/sink instabilities, and atmospheric conditions has resulted in an analytic wake transport and decay model with increased accuracy and improved predictive capabilities. (Author).
Download or read book Extimation of Wake Vortex Advection and Decay Using Meteorological Sensors and Aircraft Data written by Kathryn Marie Butler and published by . This book was released on 1993 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Vortex Forecast System written by S. M. Belotserkovsky and published by [Montréal] : Transportation Development Centre. This book was released on 1999 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Predicted Aircraft Wake Vortex Transport and Comparison with Experiment Volume II Appendixes written by M. R. Brashears and published by . This book was released on 1974 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: ;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.
Download or read book Prediction of Aircraft Wake Vortices During Takeoff and Landing written by Grégoire S. Winckelmans and published by [Montréal] : Transportation Development Centre. This book was released on 1999 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex wakes of Aircrafts written by A.S. Ginevsky and published by Springer. This book was released on 2010-10-26 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
