Aircraft Wake Safety Problem
Problems of Investigation of Aircraft Vortex Wake Evolution and Flight Safety.
Tech Area / Field
- SAT-AER/Aeronautics/Space, Aircraft and Surface Transportation
8 Project completed
Senior Project Manager
Tocheny L V
Central Aerodynamic Institute, Russia, Moscow reg., Zhukovsky
- Japan Aircraft Development Corporation, Japan, Tokyo\nNational Aerospace Laboratory NLR, The Netherlands, Amsterdam\nBoeing Technical Research Center, Russia, Moscow\nAIRBUS Industrie, France, Blagnac\nONERA, France, Clamart
Project summaryIn developed countries, air transport continues to be the preferred mode of travel for a vast majority of citizens. However, many of the world's airports have been overloaded since the early 1980's, and traffic increases over the next 20 years will take place while very few new runways are brought into service. These trends are projected to at least double the number of takeoffs and landings at the world's largest airports, even if a full transition to wide-bodied aircraft (like the Booing 747) is realized. Therefore, the determination and possible reduction of the minimum safe separation distance between airplanes during takeoff and landing, is a critical operational problem.
The emergence of jumbo aircraft (capable of carrying approximately 1000 passengers) is expected to partially alleviate traffic congestion, but also magnifies the importance of the air safety hazard caused by strong vortex wakes. These powerful vortices, caused by the combination longitudinal and span-wise flows, are shed from aircraft wings in sheets. They are capable of remaining intact, in the vicinity of runways for 2 to 3 minutes, during which time a passenger aircraft can travel 25 km. The danger to other aircraft entering these vortices is real and potentially severe, since the resultant radical lift change can cause wing stall, structural damage or engine failure due to compressor stall.
This project will provide rigorous analysis of the vortex phenomenon, required to accurately assess its contribution to the minimum safe separation distance. It will also recommend innovations in wing design and vortex decay acceleration, for incorporation in future generations of aircraft.
The presented project is aimed at the investigation of the stability of a far-field vortex wake behind the aircraft, as well as at the development of practical recommendations on vortex decay acceleration. The following aspects of the problem are to be investigated:
a) The influence of aircraft configuration and flight regime on the near-field vortex sheet and its curling behavior into two strong vortices;
b) The stability of the far-field vortex wake dependent on initial conditions of its existence (including atmospheric factors, earth proximity and geological relief), and its life-time and decay mechanisms;
c) Safe separation distances and procedures to prevent in-flight incidents due to trailing aircraft entering the wake of the previous one during take-off and landing. This can cause a sudden radical lift change, resulting in wing stall, aircraft rollover, engine failure or structural damage.
Concrete proposals will be made on possible measures aimed at vortex wake decay acceleration and increasing air traffic safety in airport zones.
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