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.
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 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 Large Eddy Simulation of Aircraft Wake Vortices in a Homogeneous Atmospheric Turbulence written by Jongil Han and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book A Preliminary Study of a Wake Vortex Encounter Hazard Boundary for a B737 100 Airplane written by and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Technique for Simulating the Motion and Ground Effect of Aircraft Wake Vortices written by R. H. Wickens and published by . This book was released on 1975 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Numerical Simulation of Wake Vortices Behind a Transport Aircraft Wing with a Partial Span Flap written by Hiromi Kawanishi and published by . This book was released on 1995 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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 Numerical Simulation of Aircraft Vortices written by Frank Thomas Zurheide and published by . This book was released on 2009 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Vortex Wake Impact on a General aviation Aircraft Model in a Wind Tunnel Using the Airfoil Lattice written by Yu S. Mikhailov and published by . This book was released on 1996 with total page 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 Simulation of Wake Vortices Descending in a Stably Stratified Atmosphere written by Clinton E. Brown and published by . This book was released on 1974 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental water tank simulation of aircraft wake vortices descending in a stable atmosphere has indicated that the atmospheric stability stops the downward movement and in some cases produces a subsequent rebound. The tests were carried out in a large ship model basin using a rectangular planform wing. Lift coefficients were selected, and stable atmospheric conditions were obtained by temperature (density) stratification of the towing basin. The model parameters and stability conditions cover the most extreme cases to be expected in full scale flight.
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 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Initial Study of the Sensitivity of Aircraft Vortex Spacing System AVOSS Spacing Sensitivity to Weather and Configuration Input Parameters written by Stephen E. Riddick and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study has been performed on a computer code modeling an aircraft wake vortex spacing system during final approach. This code represents an intial engineering model of a system to calculate reduced approach separation criteria needed to increase airport productivity. This report evaluates model sensitivity toward various weather conditions (crosswind, crosswind variance, turbulent kinetic energy, and thermal gradient), code configurations (approach corridor option, and wake demise definition), and post-processing techniques (rounding of provided spacing values, and controller time variance).
