The Looming Crisis of Air Traffic Capacity - Can Vortex Dynamics Help

Fazle HussainDept of Mech Engr, Univ of HoustonCurrently, Moore Distinguished Scholar, CaltechCullen Distinguished ProfessorDirector, Institute of Fluid Dynamics and TurbulenceABSTRACTBy 2025, the air traffic capacity will be tripled, demanding a tripling of runways at major airports of the world. Primarily mandated by aircraft separation for safe flight, this is not only already a challenge during takeoffs and landings, but will become a major problem also during cruise in the crowded skies. Motivated by this scenario, we propose a method of breaking up the trailing vortices and inducing their rapid decay so that separation between aircraft can be significantly reduced, thus minimizing the need for additional runways and flight delays.We study via direct numerical simulation the evolution of a vortex column embedded in fine-scale turbulence. We then explore three potential mechanisms for core perturbation growth:
(a) centrifugal instability due to vortex circulation overshoot, (b) Kelvin wave growth in the core due to resonance with the external turbulence, and (c) transient growth of perturbations in the normal-mode-stable vortex. We
show that transient growth of bending waves can produce orders of magnitude growth in core turbulence and hence possible breakup of trailing vortices and their faster decay - particularly at Reynolds numbers relevant to aircraft trailing vortices.

Location: Seaver Science Library, Rm 150

Audiences: Everyone Is Invited

Contact: April Mundy