Download or read book A Coupled Probabilistic Wake Vortex and Aircraft Response Prediction Model written by Thijs Gloudemans and published by . This book was released on 2016 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Two phase Aircraft Wake Vortex Model written by Frank Holzäpfel and published by . This book was released on 2003 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic two phase aircraft wake vortex model further development and assessment written by Frank Holzäpfel and published by . This book was released on 2005 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Determination of Aircraft Response to Turbulence at Low Altitudes written by John A. Dutton and published by . This book was released on 1968 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of the distribution of maxima exceedance statistics developed by S.O. Rice is combined with available information on atmospheric turbulence in an attempt to predict the statistics of aircraft responses. Details of the theoretical method are expounded, and the turbulence is assumed to be a Gaussian process to permit explicit calculation of the desired probability functions. Data from B-66 and F-106 gust investigations are combined with theoretical results to compute the statistics of maxima and exceedances for a variety of special cases. Predictions made using Gaussian assumptions disagree, in an apparently significant way, with empirically determined exceedance statistics. It is concluded that either the Gaussian assumption is not tenable, or the empirical data are inconsistent. Methods to utilize the actual distribution of turbulence are investigated. Straightforward approaches will probably not be practical unless the turbulence possesses a nearly Gaussian joint distribution for the velocity and the first two derivatives. (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 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 Efficient Probabilistic Structural Response Prediction for Aircraft Turbulence and Offshore Wave Loading written by Luke Lambert and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Candidate Wake Vortex Strength Definition for Application to the NASA Aircraft Vortex Spacing System AVOSS written by David A. Hinton and published by . This book was released on 1997 with total page 38 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 Science & Business Media. This book was released on 2009-07-07 with total page 166 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.
Download or read book Wake Vortex Separation Standards written by David Burnham and published by . This book was released on 1997 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wake vortex separation standards are used to prevent hazardous wake vortex encounters. A 'safe' separation model can be used to assess the safety of proposed changes in the standards. A safe separation model can be derived from an encounter hazard model and a vortex decay model. This report presents subsequent developments and applications of such a model which was first developed in the early 1980s. A static encounter hazard model is coupled with a decay model based on sodar measurements of vortex decay. The separation standards and procedures used from 1976 to 1994 are assumed to be safe based on the absence of IFR accidents. Various versions of the model are used to assess how aircraft should be classified and to evaluate the safety of a possible four-class aircraft separation system. Recommendations are made for ways of improving the safe separation models.
Download or read book Meteorology and Wake Vortex Influence on American Airlines Fl 587 Accident written by Fred H. Proctor and published by BiblioGov. This book was released on 2013-07 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric environment surrounding the crash of American Airlines Flight 587 is investigated. Examined are evidence for any unusual atmospheric conditions and the potential for encounters with aircraft wake vortices. Computer simulations are carried out with two different vortex prediction models and a Large Eddy Simulation model. Wind models are proposed for studying aircraft and pilot response to the wake vortex encounter.
Download or read book Meteorology and Wake Vortex Influence on American Airlines Fl 587 Accident written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-03 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric environment surrounding the crash of American Airlines Flight 587 is investigated. Examined are evidence for any unusual atmospheric conditions and the potential for encounters with aircraft wake vortices. Computer simulations are carried out with two different vortex prediction models and a Large Eddy Simulation model. Wind models are proposed for studying aircraft and pilot response to the wake vortex encounter.Proctor, Fred H. and Hamilton, David W. and Rutishauser, David K. and Switzer, George F.Langley Research CenterMETEOROLOGY; AIRLINE OPERATIONS; ACCIDENT INVESTIGATION; VORTICES; AIRCRAFT WAKES; CIVIL AVIATION; LARGE EDDY SIMULATION; TURBULENCE; STABILITY; CRASHES; AIRCRAFT PILOTS; AIRCRAFT SAFETY; VELOCITY DISTRIBUTION; WIND PROFILES; WEATHER
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 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 Nwra Avoss Wake Vortex Prediction Algorithm 3 1 1 written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-20 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides a detailed description of the wake vortex prediction algorithm used in the Demonstration Version of NASA's Aircraft Vortex Spacing System (AVOSS). The report includes all equations used in the algorithm, an explanation of how to run the algorithm, and a discussion of how the source code for the algorithm is organized. Several appendices contain important supplementary information, including suggestions for enhancing the algorithm and results from test cases.Robins, R. E. and Delisi, D. P. and Hinton, David (Technical Monitor)Langley Research CenterALGORITHMS; PREDICTION ANALYSIS TECHNIQUES; WING TIP VORTICES; AIRCRAFT WAKES; AIRCRAFT APPROACH SPACING; COMPUTER PROGRAMS; SOURCE PROGRAMS; ARCHITECTURE (COMPUTERS)
Download or read book Aircraft Wake Vortex Evolution and Prediction written by Frank Holzäpfel and published by . This book was released on 2005 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aircraft Dynamic Loads Generated in Wake Vortex Encounters written by Carles Suñer Perucho and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study illustrated in these pages was developed in the Structural Dynamics and Aeroelasticity Department of the Military Aircraft division of Airbus Defence and Space in Getafe, Madrid (Spain). That department is a multidisciplinary one involving several categories. Some of its competences are the analysis of impacts, acoustics and vibrations for the aircraft and all their systems. Also, the dynamic response of the aircraft to different events is part of the tasks for that department. It is in that field where this project is located. Wake vortex encounters are a dynamic phenomenon similar to other excitations faced by aircraft in its usual operation. That excitation will induce dynamic loads in the aircraft structures as it passes through the wake. Obtaining and analyzing those loads are the main aims of this study. First, it is important to introduce the concept of aircraft wake. In order to achieve the goals of the study, it is necessary to start with the basics of the problem. This is the acknowledgement of the physics of aircraft wakes and how they are generated. Then, how those wakes act as an excitation for other aircraft as they perturb the velocity field of the air. Once the aircraft wakes are introduced, the next step consists of explaining the corresponding aircraft that will face those encounters. In this case, the particular aircraft is an Airbus A400M because that was the one used by Airbus Defence and Space in the campaign of the wake vortex encounters. The following considerations involve the procedures of the Structural Dynamics department in the computation of the numerical simulation for that kind of event. Therefore, it is necessary to know what the tools available for the resolution of this problem are and which aspects face each one. Furthermore, the software and models used in this study have been validated with flight tests and they are an excellent representation of the aircraft and problem considered. After the presentation of the problem, the aircraft considered and tools used, the wake model is the next aspect of study. This is one of the widest fields of aircraft wakes. Having a good wake model is necessary for the accuracy of the results and the main tasks are focused on the wake aging model. That is how the wake evolves and changes as times goes by. With all that, the last aspect of this study is the computation of the dynamic loads induced in wake vortex encounters. As it is an event that is not considered in aircraft regulations, it was difficult to define a particular scenario that is representative of the problem. For that reason, a stochastic analysis of the problem has been chosen to obtain the aircraft loads generated in this kind of event. This analysis consists of scattering the input variables affecting the problem and executing a high number of simulations. In that way, it is possible to derive a statistical behavior of the load response and establish a probability of occurrence for the results obtained. Finally, comparing those results with the reference loads of the aircraft, it is feasible to predict whether wake vortex encounters could be a significant event for the aircraft structure during its operational life.
