Aircraft Wake Vortex Evolution and Prediction

Kurzfassung

Aircraft trailing vortices constitute both a kaleidoscope of instructive fluid dynamics phenomena and a challenge for the sustained development of safety and capacity of the air-transportation industry. The current manuscript gives an overview on the wake vortex issue which commences at its historical roots and concludes with the current status of knowledge regarding the nature and characteristics, and the modeling of aircraft wakes. The incentive of today's wake vortex research still rests on the empirically motivated separation standards between consecutive aircraft introduced in the 1970s. These aircraft separations fix the capacity of congested airports in a rapidly growing aeronautical environment. Advanced solutions for dynamically adjusted weather-dependent aircraft separations hold significant economizations without compromising safety. Appropriate separation distances are also crucial for the success of the twin-deck A380 airliner which will enter service in 2006. On the search for technical answers, applied wake vortex research must always consider its complex operational, political, and business environment and it must be aware of its serious responsability for passenger safety. The extensive introductory survey concludes with a delineation of scientific windows on wake vortex physics, connected chances and limitations, and a list of controversial issues that motivate the author's contributions to the field. The second part of the manuscript guides through these contributions which are detailed in eight integrated journal publications. Four of these papers treat the analysis of wake vortex evolution and decay in the stably stratified, sheared, turbulent, and convective atmospheric boundary layer and lead to a theoretical foundation for the physics of vortex decay. A subgrid-scale closure modification for large eddy simulation with strong streamline curvature is suggested and the accuracy of lidar measurements of wake vortices is assessed. Finally, the devised parametric real-time wake vortex prediction model is introduced. Validations against observation data from five different field deployments indicate that the probabilistic model has reached a high degree of maturity which suggests that the model may enter operational use in the near future.