Wake-vortex characteristics of military-type aircraft measured at Airport Oberpfaffenhofen using the DLR Laser Doppler Anemometer

The DLR ground-based cw Doppler lidar was used for experimental investigati ons of wake vortices gene rated by military-type aircraft, including fixed- wing as well as rotor-wing aircraft. The measurements were mainly focused o n the roll-up phase of the vortices. The experimental data has been analyse d regarding vortex structure and circulation, partly also regarding their t emporal development. The influence of flight parameters was measured during consecutive aircraft fly-bys. Small variations in the velocity profiles co uld be observed which were overlayed by the signatures of the variable wind and turbulence field. This problem can be: solved on a statistical basis b y measuring many cases under the same atmospheric conditions. The influence of aircraft design could be demonstrated by comparison of the vortex signa tures of two B707-tyoe aircraft showing pronounced design differences, name ly a standard B707 and a AWACS E3A. (C) Elsevier, Paris.