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

Abstract

The DLR ground-based cw Doppler lidar was used for experimental investigations of wake vortices generated by military-type aircraft, including fixed-wing as well as rotor-wing aircraft. The measurements were mainly focused on the roll-up phase of the vortices. The experimental data has been analysed regarding vortex structure and circulation, partly also regarding their temporal development. The influence of flight parameters was measured during consecutive aircraft fly-bys. Small variations in the velocity profiles could be observed which were overlayed by the signatures of the variable wind and turbulence field. This problem can be solved on a statistical basis by measuring many cases under the same atmospheric conditions. The influence of aircraft design could be demonstrated by comparison of the vortex signatures of two B707-type aircraft showing pronounced design differences, namely a standard B707 and a AWACS E3A. © Elsevier, Paris.