Characterization of Aircraft Wake Vortices by 2-(mu)m Pulsed Doppler Lidar

The 2-(mu)m pulsed Doppler lidar, already successfully used for wind and turbulence measurements, has been modified for long-range wake-vortex characterization. In particular, a four-stage data processing algorithm has been developed to achieve precise profiles of tangential velocities from which the vortex parameters such as trajectories, core separation, tilt angle, and circulation can be derived. The main advantage of the pulsed lidar is its long-range capability of more than 1 km. This allows for observations over long periods from the moment of wake generation to a progressed state of vortex decay. With the field experiment at Tarbes airfield the potential of the 2-(mu)m pulsed Doppler lidar for full-scale wake-vortex characterization has been demonstrated. Two examples showing the parameters of wake vortices generated by large transport aircraft A(LTA)-type aircraft will be presented.