Vortex filament and global instability analysis of the crow mode

Abstract

Aircraft trailing vortices and their wakes are important to understand in order to shorten the minimum aircraft distances for safe operation in commercial flights. The mechanisms of wake destruction are studied by predictions by both inviscid vortex filament and viscous BiGlobal instability analyses. The two methods have already been applied to the wake problem, but a more detailed comparison is carried out here. The results show excellent agreement between the two methodologies predicting the long wave symmetric instability of a counter-rotating pair of vortices, namely the Crow instability, even at low Reynolds numbers.