Wake vortex evolution during approach and landing with and without plate lines

Data from numerical simulations and two field measurement campaigns are used to investigate aircraft wake vortex evolution during final approach and landing with and without a plate line. A new hybrid simulation method is employed to capture wake vortex evolution from early roll-up to final decay in ground proximity. Vortex decay is driven by the turbulence of the aircraft wake itself, the interaction of the wake vortices with the ground, the so-called end effects triggered by the sudden loss of lift during touchdown, and it is artificially augmented by a plate line installed a few hundred meters from the runway threshold. The field experiments WakeMUC at Munich airport and WakeOP at special airport Oberpfaffenhofen corroborate and complement the findings of the simulations. The end effects together with an acceleration of the decay in close ground proximity significantly accelerate vortex decay nearby the runway. In view of the fact that the probability to encounter wake vortices is distinctly increased in ground effect, the described mechanisms ensure the required safety of air traffic operations. Experiments and simulations demonstrate that plate lines appreciably accelerate wake vortex decay and interfere favorably with end effects. This way safety can be further increased during the flight phase with most reported encounters.