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Aircraft Wake Vortices Characterization And Alleviation
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Book Synopsis Aircraft Wake Vortices Characterization and Alleviation by : Omer Ali El-Sayed
Download or read book Aircraft Wake Vortices Characterization and Alleviation written by Omer Ali El-Sayed and published by . This book was released on 2010 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The serious impact of the trailing vortices from large aircraft is well known. Many examples exist of the damage caused to following aircraft caught up in the swirling wake shed from an upstream aircraft. Motivation behind the present investigation is the alleviation of the rolling moment induced on the following aircraft by means of a differential spoiler setting DSS's. An experimental investigation on a wing tip vortex generated by generic aircraft model, Subsonic Wall Interference Model (SWIM) in plain and flapped wing configurations was conducted in a low speed wind tunnel at Korean Aerospace Research Institute (KARI). Particle image velocimetry was used to characterize wing tip vortex structures as well as to distinguish and quantify vortex meandering and further remove its effects. In subsequent experiments investigation on wake vortices has been carried out in the international Islamic University Malaysia (IIUM) low speed wind tunnel for the evaluation of differential spoiler settings (DSS) capabilities in modifying the span-wise wing load and further reduces the wake vortex hazard. Advanced PIV technique was used to measure the wake velocities at four cross-section planes down-stream of the aircraft half model in the near and extended near wake field. Model was investigated at high lift configuration as well as at four DSS configurations believed to modify the span-wise wing loading (two inboard and two outboard loading cases). Results reveal a noticeable inboard shift of wing loading along with the direct interaction of the spoiler's wake and flap tip vortex for the inboard loading cases. Implementation of DSS results in a substantial redistribution of the flap tip vortex circulation with a diameter of the merged vortex increased by a factor of up to 2.72 times, relative to the undisturbed flap tip vortex. Inspection of the cross-stream distribution of axial vorticity shows up to 2.33 times reduction in the peak vorticity value. A 44% decrease of the maximum cross-flow velocity was recorded for the case of deployed spoilers relative to undisturbed flap tip vortex maximum cross-flow velocity. The wing tip vortex experiences the effect of wing load modification but doesn't show appreciable difference, both in terms of cross-flow velocity and local circulation distribution. Evaluations of the outboard loading results indicate a limited diffusion experienced by the vortex due to the increased level of turbulence. Influence of DSS's on the wake vortex structure emphasizes that separation distance (spoiler wake/wing-flap tips vortices) plays an important role in the favorable interaction expected. Finally assessment of the DSS's capabilities as a wake vortex attenuation device reveals, while position of the maximum induced rolling moments in the flap tip area is little influenced by the DSS's, the maximum induced rolling moment coefficient was reduced to a nearly one third relative to the undisturbed flap tip vortex value.
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 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 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 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 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 Analysis of Wake Vortex Flight Test Data Behind a T-33 Aircraft by :
Download or read book Analysis of Wake Vortex Flight Test Data Behind a T-33 Aircraft written by and published by . This book was released on 1975 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
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 Aircraft Wake Vortex Characteristics from Data Measured at John F. Kennedy International Airport by :
Download or read book Aircraft Wake Vortex Characteristics from Data Measured at John F. Kennedy International Airport written by and published by . This book was released on 1978 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aircraft Wake Vortices by : T. E. Sullivan
Download or read book Aircraft Wake Vortices written by T. E. Sullivan and published by . This book was released on 1990 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720524847 Total Pages :66 pages Book Rating :4.5/5 (248 download)
Book Synopsis Flight Data Reduction of Wake Velocity Measurements Using an Instrumented Ov-10 Airplane by : National Aeronautics and Space Administration (NASA)
Download or read book Flight Data Reduction of Wake Velocity Measurements Using an Instrumented Ov-10 Airplane written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-31 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of flight tests to measure the wake of a Lockheed C- 130 airplane and the accompanying atmospheric state have been conducted. A specially instrumented North American Rockwell OV-10 airplane was used to measure the wake and atmospheric conditions. An integrated database has been compiled for wake characterization and validation of wake vortex computational models. This paper describes the wake- measurement flight-data reduction process.Vicroy, Dan D. and Stuever, Robert A. and Stewart, Eric C. and Rivers, Robert A.Langley Research CenterFLIGHT TESTS; WAKES; VELOCITY MEASUREMENT; MATHEMATICAL MODELS; PROCEDURES; C-130 AIRCRAFT; DATA BASES; METEOROLOGY; VORTICES; RESEARCH AIRCRAFT
Book Synopsis Aircraft Wake Vortex Characteristics from Data Measured at John F. Kennedy International Airport by : W. R. Eberle
Download or read book Aircraft Wake Vortex Characteristics from Data Measured at John F. Kennedy International Airport written by W. R. Eberle and published by . This book was released on 1978 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data from 1320 aircraft flybys at Kennedy International Airport, Jamaica, New York, in 1975 were processed and stored in a computerized vortex data management system. The data were selectively recalled to determine vortex characteristics pertinent to the design of an effective wake vortex avoidance system. Vortex and meteorological characteristics which are relevant to the design of an effective wake vortex avoidance system are discussed from an analytical viewpoint as well as from an analysis of the data. Several formulations for feedback of vortex sensor information to provide vortex prediction are presented. Several wake vortex avoidance system designs are shown. (Author).
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.
Book Synopsis Accelerated Destruction of Aircraft Wake Vortices by : Stanford University. Department of Aeronautics and Astronautics
Download or read book Accelerated Destruction of Aircraft Wake Vortices written by Stanford University. Department of Aeronautics and Astronautics and published by . This book was released on 1997 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aircraft Wake Vortex Spacing System (AVOSS) Performance Update and Validation Study by : David K. Rutishauser
Download or read book Aircraft Wake Vortex Spacing System (AVOSS) Performance Update and Validation Study written by David K. Rutishauser and published by . This book was released on 2001 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Analysis of Predicted Aircraft Wake Vortex Transport and Comparison with Experiment. Volume II. Appendixes by : M. R. Brashears
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.
