Development and validation of new simulation method for wake-vortex decay in ground proximity with artificial enhancements

Abstract

Air traffic congestion is one of the most prominent challenges that hinders the growth of air travel. According to the International Air Transport Association (IATA), which represents 83% of global air traffic, there will be 7.2 billion air travellers in 2035. This is almost double the number of air travellers in 2014. One of the main factors slowing down the increase in airport capacity is the limited frequency of landings and take-offs. The time and distance separating two consecutive landing aircrafts is determined by the strength of the pair of wing-tip wake-vortices of the leading aircraft, that pose a danger to the following aircraft. Although a few reduced separation standards have already been implemented at selected airports worldwide, it still persists to be a hurdle due to the limited knowledge of aircraft wake vortex decay. Hence, the aim of this study is to reduce the lifespan of an aircraft wake vortex, thereby paving a way for tighter and safer staggering of aircrafts in the vicinity of the airport. The main source of energy for the wake-vortices is the aircraft’s induced drag ,which in turn, depends on the lift distribution over an aircraft wing. Therefore, it is concluded that modifying the aircraft lift distribution is one of the best ways to reduce the intensity of the wake-vortices. Reducing the intensity of these aircraft wake-vortices will eventually result in a shorter lifespan of vortices in the atmosphere, thus reducing the separation distances and increasing the airport capacity. In this dissertation, the relationship between the lift distribution of an aircraft and its wake-vortices is studied, by developing an effective initialisation method for the Temporal Large Eddy Simulation (LES), based on the Prandtl Lifting-Line Theory. This unique methodology is categorised as Quasi-temporal LES, which incorporates the roll-up phase of the multiple wake-vortices shed behind an aircraft, their evolution into a single pair of counter-rotating vortices and their eventual decay.