Wake vortex detection and monitoring

Coherent laser radar (CLR) or lidar is a powerful technique for the detection and study of aircraft wake vortices. The technique measures the Doppler shift of light scattered from atmospheric particles, and hence infers the line-of-sight flow velocity allowing a picture of vortex flow to be built up. Monitoring of vortices at ranges exceeding a few hundred metres is best carried out using pulsed lidar: results of field trials using the MFLAME system will be presented, including an analysis of the potential for on-board detection. Detailed measurements at short range are better obtained with continuous-wave (CW) lidar, and work will be presented on characterisation of wake vortices by CW lidar measurements. These studies have potential to aid low-vortex wing design, and for quantifying the vortex hazard from existing aircraft. Finally, the possibility for employing lidar in reduced-scale studies (catapult and wind tunnel) will be discussed. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.