Review of real-time wake vortex prediction models
Although wake vortex behavior has been studied many years, serious controversies existed regarding decay and transport, including Reynold's number effects and influence from weather. Measurements and analysis during NASA's Aircraft Vortex Spacing System (AVOSS) project emphasized the importance of weather on vortex transport and decay. It was clear that the intensity of atmospheric turbulence does affect the decay rate of a wake vortex, with the characteristics of this decay having little in common with the decay of low-Reynold's number vortices. A primary contribution during this program was the development of a real-time physics-based wake prediction model called the AVOSS Prediction Algorithm (APA), which is based on Sarpkaya's “out of ground effect” decay model. In a demonstration at DFW airport, the APA model predicted safe aircraft spacings between leading and following aircraft based on predictions of positions and strengths of aircraft wake vortices. This model has been a “jumping board” for the development of similar models, such as the TASS Derived Algorithms for Wake Prediction (TDAWP) and the Deterministic Two-Phase (D2P) model. This paper will describe these models and their intent of operation, as well as show comparisons with wake vortex measurements. Also described will be limitations to these models and future improvements.