| Title | Estimates of the initial vortex separation distance, bo, of commercial aircraft from pulsed lidar data |
|---|---|
| Record ID | 47496 |
| Personal Name Creator |
Delisi, Donald P.; Pruis, Matthew J.; Wang, Frank Y.; Lai, David Y. |
| Source | 10p. in various pagings; 51st AIAA Aerospace Sciences Meeting, January 7-10, 2013, Grapevine, TX |
| Corporate Creator | NorthWest Research Associates, Inc., Bellvue, WA; John A. Volpe National Transportation Systems Center (U.S.) |
| Publisher | American Institute of Aeronautics and Astronautics |
| Publication Date | 20130107 |
| Language | English |
| Abstract | An aircraft in flight generates multiple wake vortices, the largest of which are a result of the lift on the wings. These vortices rapidly roll up into a counter-rotating vortex pair behind the aircraft. The initial separation between the centroids of vorticity behind the aircraft, or the cores of the resulting vortex pair, is commonly denoted as bo. This separation distance is used to estimate the initial vortex strength (circulation) and to nondimensionalize both time and circulation behind the aircraft. Thus, bo is an important parameter in nondimensionalizing aircraft wake measurements. For an elliptically loaded wing, bo = (/4)s, where s is the wingspan of the generating aircraft. The initial descent velocity of the vortex system behind the aircraft, Vo, is proportional to bo -2. Thus, from estimates of Vo from lidar measurements, we can estimate bo. Estimates of Vo from lidar measurements of vortex altitude vs. time are presented in the Out of Ground Effect (OGE)region for aircraft arriving at Denver International Airport and San Francisco International Airport. Estimates of bo for these aircraft are then obtained. These measurements suggest that, while some estimates of bo from commercial aircraft are close to the value based on elliptical wing loading, some aircraft have distinctly nonelliptical values of bo. |
| Rosap ID | dot:9886 |
| Rosap URL | https://rosap.ntl.bts.gov/view/dot/9886 |
| TRT Terms | Aircraft; Vortices; Wakes; Flow; Aircraft separation; Laser radar; Flow measurement; Mathematical models; Aircraft wings; Velocity measurement |
| Classification | NTL - AVIATION - AVIATION; NTL - AVIATION - Air Traffic Control |
| Geographical Coverage |
Denver (Colorado); San Francisco (California) |
| Report Number | AIAA 2013-0365 |
| Availability | Volpe National Transportation Systems Center, Technical Reference Center |
| Resource type | Proceedings |
| URL | https://ntlrepository.blob.core.windows.net/lib/47000/47400/47496/AIAA-2013-0365_EstimatesOfInitialVortex.pdf |
| Format | |
| Database | NTL Digital Repository |