Long wave instability of aircraft wake vortex under shear crosswind

To a large extent, dynamic instabilities dominate the lifespan of aircraft wake vortices, which is one of the most important factors that determine the flight separation. Considering that the wake vortex instability might be affected by crosswind, the long-wave instability of the aircraft wake vortex under shear crosswind condition is investigated using linear stability analysis method for the first time. It is found that the growth rate of the longwave instability is reduced under the influence of the strain field exerted by the crosswind shear, and the vortex filaments are inclined additionally along the crosswind speed gradient. Furthermore, the curvature corrected vortex filament method is adopted to simulate the dynamic instability. The numerical experiment results agree well with the theoretical prediction.