[GTP] Seminar- Dr. Fazle Hussain-Tomorrow

[Silvia Gentile]

Fazle Hussain
Departments of Mechanical Engineering, Physics, and Geosciences
University of Houston

September 24, 2010
Foothills Laboratory 2, Room 1022
Lecture 1:30pm
The Looming Crisis in Air Traffic Capacity -Can Vortex Dynamics Help?

The air traffic capacity is projected to be tripled by 2025, demanding a 
tripling of runways at major airports of the world. Safe aircraft 
separation to avoid wake hazard is not only already a challenge during 
takeoffs and landings, but will become a major problem also during 
cruise in the crowded skies. We propose a method of breaking up the 
trailing vortices and inducing their rapid decay so that separation 
between aircraft can be significantly reduced. We study via direct 
numerical simulation the evolution of a vortex column embedded in 
fine-scale turbulence, and then explore three potential mechanisms for 
core perturbation growth:

   1. Centrifugal instability due to vortex circulation overshoot,
   2. Kelvin wave growth due to resonance with the external turbulence, and
   3. 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 -particularly at Reynolds numbers relevant to aircraft.


-- 
Silvia Gentile
NCAR IMAGe
1850 Table Mesa Drive
Boulder, Co 80305
www.image.ucar.edu