Observation of Aircraft Wake Vortex Based on Coherent Doppler Lidar

Coherent Doppler Lidar (CDL) is frequently used to detect wake vortexes in the clear days because of its advantages of high precision, high spatial and temporal resolution and so on. To improve the observation efficiency of wake vortexes and realize the fast processing and real-time displaying of data, the wake vortex observation experiments were performed in Sichuan province in 2018 and a fast method for identification of wake vortexes was presented based on the radial velocity and spectral width given by CDL. In addition, the wake vortex evolution processes of typical aircraft types were analyzed based on the proposed method. The results show that the wake vortex evolution tendency is similar for all different aircraft types, which first occurs at about 50 m above the ground, then diffuses downward and outward, and the circulation of wake vortexes gradually decreases. However, it is accompanied by the short-time increase of circulation under the influence of the near-ground effect. With the decrease of aircrafts' weight and wingspan, the dissipation time of wake vortexes decreases, the initial distance between the cores of the right and left wake vortexes gets short, the fusion phenomenon of spectral width becomes more obvious, and the time for the disappearance of this phenomenon increases.