Received 13 March 2006; revision received 9 June 2006; accepted for publication 4 August 2006. Copyright © 2006 by Graham T. Spence, Alan Le Moigne, David J. Allerton, and Ning Qin. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Copies of this paper may be made for personal or internal use, on condition that the copier pay the $10.00 per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923; include the code 0021-8669/07 $10.00 in correspondence with the CCC.
Research Associate, Automatic Control and Systems Engineering, Mappin Street. Member AIAA.
Research Associate, Mechanical Engineering, Mappin Street. Member AIAA.
Professor, Automatic Control and Systems Engineering, Mappin Street.
Professor, Mechanical Engineering, Mappin Street. Associate FellowAIAA.
THE effect of aircraft generated trailing wake turbulence on an encountering aircraft can be hazardous, particularly during the takeoff and landing phases, as seen in the American Airlines Flight 587 accident over New York on 12 November 2001 . Wake vortices [2,3] generated by civil transport aircraft are the result of the lift generated by the aircraft wing and tail and so their formation is unavoidable. Consequently, aviation authorities impose strict minimum separation rules for departures and approaches in an attempt to minimize the likelihood of encountering wake vortices. However, these rules also restrict the capacity of airports. With the continued growth in air traffic, there is increasing interest toward gaining a greater understanding of wake vortex behavior, not only in terms of safety but also from the perspective of increasing airport capacity. The ability to model the effect of aircraft trailing wake vortices in real time provides several benefits: 1) training flight crew to cope with potentially hazardous situations, including wake encounters; 2) aiding the determination of acceptable safety limits or passenger comfort aspects in the event of a wake encounter; and 3) validation of wake vortex models in comparison with events that have been experienced during real-life wake encounters. Several analytic models of the post roll-up flowfield of aircraftwake vortices exist. A summary of these vortex models is presented by Gerz et al. . These models are suitable for real-time use and some have been used in previous flight simulation studies [5–8]. However, until recently, most real-time wake turbulence encounter simulation studies have been limited to models that describe the velocity field in two dimensions. Although computationally cheap, such approaches lack the ability to include the three-dimensional flow structures that are observed in actual wake turbulence . Realtime studies of airplane encounters with analytic models of perturbed wake vortex systems are now emerging . An attempt at using large eddy simulation (LES) data to form the basis of an analytic vortex model has also been presented . This study derived 2-D velocity flowfields from 3-D LES data. 3-D instability effects were then created by varying the flowfield in a sinusoidal fashion. Until now, no real-time aircraft-wake encounter simulations have attempted to directly access the data from LES to provide a realtime model of a wake vortex system. This is the major contribution described in this paper. A similar model has been used in a study of the influence of aircraft encountering wake vortices in a convective boundary layer , however, it is not a real-time model. The idea of...