Numerical Study of Four-Vortex Aircraft Wakes

Kurzfassung

Instabilities evolving on simplified vortex wakes, built up by two pairs of counter-rotating vortices, are investigated numerically. Two configurations are considered: the first circulation and spacing ratio corresponding to a wide-body airliner in landing configuration and a modified set-up with a strong inner vortex pair. The investigation shows that a strong inner pair is necessary for the instability to cause a large increase of vortex radii of the outer vortex pair. This increase in turn leads to a rapid decay of rolling moment.