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Wake Vortex Modelling And Simulation For Air Vehicles In Close Formation Flight
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Book Synopsis Wake Vortex Modelling and Simulation for Air Vehicles in Close Formation Flight by :
Download or read book Wake Vortex Modelling and Simulation for Air Vehicles in Close Formation Flight written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this research is to develop realistic models of aerodynamic cross-coupling e ects that can be incorporated in real-time or near real-time simulations of Unmanned Aerial Vehicles (UAVs) in close formation flight. These would permit the assessment of the risks and issues associated with wake vortex evolution and encounter and the analysis of their consequences on the design of automatic control systems and the development of safe and reliable operating procedures. A number of wake vortex modelling techniques that can be used in formation flight simulations are reviewed. A novel Wake Vortex Model (WVM) is developed, implemented, verified, validated and successfully integrated within a Matlab/Simulink simulation environment. The code, named ELL because it is based on Weissinger's extended lifting line theory, meets the following requirements: (i) it is generic and can easily be adapted to accomodate any wing planform and air vehicle configuration; (ii) it is computationally rapid enough to be used in real-time or near real-time simulations; (iii) and it is sufficiently representative to support studies of aerodynamic interaction between multiple air vehicles during formation reconfiguration and air-to-air refuelling simulations. Simulink test scenarios of two Aerosonde UAVs are developed to test and validate the use of ELL within simulation models, and the simulation environment is interfaced with visualisation tools in order to facilitate the evaluation of multiple air vehicle dynamic interaction.
Book Synopsis Vortex wakes of Aircrafts by : A.S. Ginevsky
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.
Book Synopsis Wake Turbulence by : National Research Council
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.
Book Synopsis Simulating the Lifecycle of Aircraft Wake Vortices by : Daniel Guy Schauerhamer
Download or read book Simulating the Lifecycle of Aircraft Wake Vortices written by Daniel Guy Schauerhamer and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To better understand aircraft wake behavior with the goal to increase flight safety and airport capacity, the aircraft wake vortex lifecycle was simulated using computational fluid dynamics. Using a build-up approach, best practices for wing-tip vortex roll-up were developed starting with a simple inviscid vortex, and building up in complexity to a finite wing and full aircraft. Validation of the best practices was accomplished with comparisons to wind tunnel data. Best practices were then applied to the German Aerospace Center F11 wind tunnel model and the NASA Common Research Model with validation of results with wind tunnel measurements. Vortex sensitivity to aircraft configuration were explored by changing the details of the F11 model, and by adding a generic winglet to the Common Research Model. Results demonstrated that the wake vortex changed significantly with aircraft configuration. The wake of the Common Research Model was used to initialize two-dimensional evolution studies which propagated the wake system to 10 wing spans downstream. Best practices were developed to demonstrate low numerical error and the computational savings of using adaptive mesh refinement. Three-dimensional simulations were carried out with the Common Research Model to resolve 10 wing spans downstream, however with a coarser-than-desired mesh due to computational limitations. The solution was used to initialize three-dimensional decay simulations. A testbed case of wake vortex decay was used to develop best practices and quantify error sources for decay simulations in a cost-effective manner. Those best practices were applied to the Common Research Model decay simulation. Results throughout the research were compared to idealized vortex models that in practice are used to initialize decay simulations. For all comparisons, including the aircraft effects resulted with significant differences to the idealized vortex models. Including the aircraft effects in the simulations resulted in more accurate wake results.
Book Synopsis Response of Aircraft Encountering Aircraft Wake Turbulence by : Robert C. Nelson
Download or read book Response of Aircraft Encountering Aircraft Wake Turbulence written by Robert C. Nelson and published by . This book was released on 1974 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation deals with the dynamic behavior of an airplane encountering aircraft wake turbulence. A digital computer simulation was developed to study the response of an aircraft flying into a trailing vortex wake. The simulation includes the complete six degree of freedom equations of motion, a description of the vortex velocity field, unsteady aerodynamics, and pilot control input. The parameters included the penetration angle, separation distance, aircraft size, and pilot control input. Predicted vortex induced motions are presented for general aviation, business, and light jet transport type aircraft.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781794256132 Total Pages :32 pages Book Rating :4.2/5 (561 download)
Book Synopsis Documentation for Three Wake Vortex Model Data Sets from Simulation of Flight 587 Wake Vortex Encounter Accident Case by : National Aeronautics and Space Adm Nasa
Download or read book Documentation for Three Wake Vortex Model Data Sets from Simulation of Flight 587 Wake Vortex Encounter Accident Case written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-18 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document contains a general description for data sets of a wake vortex system in a turbulent environment. The turbulence and thermal stratification of the environment are representative of the conditions on November 12, 2001 near John F. Kennedy International Airport. The simulation assumes no ambient winds. The full three dimensional simulation of the wake vortex system from a Boeing 747 predicts vortex circulation levels at 80% of their initial value at the time of the proposed vortex encounter. The linked vortex oval orientation showed no twisting, and the oval elevations at the widest point were about 20 meters higher than where the vortex pair joined. Fred Proctor of NASA's Langley Research Center presented the results from this work at the NTSB public hearing that started 29 October 2002. This document contains a description of each data set including: variables, coordinate system, data format, and sample plots. Also included are instructions on how to read the data. Switzer, George F. Langley Research Center RTI/8438/006-02F
Book Synopsis Modelling of Temporal-Spatial Distribution of Airplane Wake Vortex for Scattering Analysis by : Jianbing Li
Download or read book Modelling of Temporal-Spatial Distribution of Airplane Wake Vortex for Scattering Analysis written by Jianbing Li and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft wake vortex is a pair of intensive counter-rotating airflow generated by a flying aircraft. Wake vortex is one of the most dangerous hazards in aviation because it may cause a following aircraft to roll out of control, particularly during the taking off and landing phases. The real-time detection of wake vortex is a frontier scientific problem emerging from many fields like aviation safety and atmospheric physics, and the dynamics and scattering characteristics of it remain as key problems to develop corresponding detection technologies. This chapter aims at presenting a simulation scheme for the dynamics of wake vortex under different weather conditions. For wake vortex generated in clear air, changes of the atmospheric dielectric constant produced by the density variation and water vapour variation are analysed; for wake vortex generated in rainy condition, the raindrop distribution in the wake vortex is also analysed. Both of them are essential for further analysing the scattering characteristics and developing new detection algorithms.
Book Synopsis Issues in Astronautics and Space Research: 2011 Edition by :
Download or read book Issues in Astronautics and Space Research: 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Astronautics and Space Research / 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Astronautics and Space Research. The editors have built Issues in Astronautics and Space Research: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Astronautics and Space Research in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Astronautics and Space Research: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Book Synopsis Full Capability Formation Flight Control by : Ryan K. Osteroos
Download or read book Full Capability Formation Flight Control written by Ryan K. Osteroos and published by . This book was released on 2005 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aircraft Wake Vortex Scenarios Simulation Package - Wakescene by : Frank Holzäpfel
Download or read book Aircraft Wake Vortex Scenarios Simulation Package - Wakescene written by Frank Holzäpfel and published by . This book was released on 2007 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aircraft Wake Turbulence and Its Detection by : John Olsen
Download or read book Aircraft Wake Turbulence and Its Detection written by John Olsen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 599 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of increasing airport congestion and the ad vent of large transports has caused increased interest in aircraft wake turbulence. A quantitative understanding of the interaction between an aircraft and the vortex wake of a preceding aircraft is necessary for planning future high density air traffic patterns and control systems. The nature of the interaction depends on both the characteristics of the following aircraft and the characteristics of the wake. Some of the questions to be answered are: What deter mines the full characteristics of the vortex wake? What properties of the following aircraft are important? What is the role of pilot response? How are the wake characteristics related to the genera ting aircraft parameters? How does the wake disintegrate and where? Many of these questions were addressed at this first Aircraft Wake Turbulence Symposium sponsored by the Air Force Office of Sci entific Research and The Boeing Company. Workers engaged in aero dynamic research, airport operations, and instrument development came from several count ries to present their results and exchange information. The new results from the meeting provide a current picture of the state of the knowledge on vortex wakes and their interactions with other aircraft. Phenomena previously regarded as mere curiosities have emerged as important tools for understanding or controlling vortex wakes. The new types of instability occurring within the wake may one day be used for promoting early dis integration of the hazardous twin vortex structure.
Book Synopsis Wake Vortex Separation Standards by : David Burnham
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.
Book Synopsis Aircraft Wake Vortices by : James N. Hallock
Download or read book Aircraft Wake Vortices written by James N. Hallock and published by . This book was released on 1991 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis National Academy of Sciences’ decadal plan for aeronautics : hearings by :
Download or read book National Academy of Sciences’ decadal plan for aeronautics : hearings written by and published by DIANE Publishing. This book was released on with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Proceedings of the Aircraft Wake Vortices Conference, Washington, D.C., October 29-31, 1991 by :
Download or read book Proceedings of the Aircraft Wake Vortices Conference, Washington, D.C., October 29-31, 1991 written by and published by . This book was released on 1992 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Study of Wake Vortex Alleviation by : Hani bin Ludin @ Jamaluddin
Download or read book Numerical Study of Wake Vortex Alleviation written by Hani bin Ludin @ Jamaluddin and published by . This book was released on 2012 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical investigation was undertaken to study the aerodynamic characteristics of wake vortices generated from an aircraft during taking-off or landing, and thus exploring the possible techniques of reducing hazard imposed to the following aircraft by means of passive wake vortex alleviation. An initial study has been carried out on passive wake vortex alleviation by using delta wing (DW) and reverse delta wing (RDW) as an add-on device. Simulations were performed using RANS turbulence model. The results were obtained and quantified at measurement section locations downstream, of x/c=1.359 and x/c=3.418 measured from leading edge point of the model. Comparison between numerical and experimental results has shown good agreement in term of aerodynamic forces for RDW, whereas the comparison is not so good for DW as far as the prediction of drag coefficient is concerned. Although the simulations capture vortex roll-up trends, the size of the vortex is not predicted correctly by RANS turbulence model. Overall, it can be concluded from the results that the wake vortex generated from DW exhibit higher tangential velocity magnitude and circulation than the one generated from RDW at a particular angle of attack (AOA) between 20o to 30o. Subsequently, a broader investigation of another passive wake vortex alleviation technique was performed to study the potential of differential spoiler setting (DSS) of a scaled, half-model aircraft in alleviating the rolling moment induced on the following aircraft. The model was simulated under high lift configuration (HLC) condition, using inherently unsteady technique adopted in LES turbulence model, for two outboard loading cases and two inboard loading cases, in addition to the baseline configuration case. The study has covered near-wake field and extended near-wake field by taking seven measurement section planes at x/b=0.345, x/b=0.444, x/b=0.658, x/b=1.076, x/b=1.794, x/b=2.691 and x/b=4.484. Comparison between numerical simulations and experimental results has shown good agreement in term of lift coefficient for all cases, and fairly acceptable agreement in term of maximum cross-flow velocity, maximum normalized total circulation and maximum induced rolling moment. However, there were some occasions where the comparison is not so good. For instance, the difference error has risen up to 40.3% in term of maximum normalized cross-flow velocity for baseline configuration. Evaluation of the results has showed promising outcomes for the inboard loading cases compared to the outboard loading cases. The interaction between spoilers' wake and outboard flap tip vortex of the inboard loading cases has reduced the tangential velocity magnitude and circulation of the wing tip vortex, and delayed vortex merging to farther distance downstream. This conclusion justifies the DSS's capabilities in wake vortex alleviation. Therefore, DSS can be considered as one of the promising techniques that can be used commercially in the future.
Book Synopsis A Candidate Wake Vortex Strength Definition for Application to the NASA Aircraft Vortex Spacing System (AVOSS) by : David A. Hinton
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:
