Development of Predictive Wake Vortex Transport Model for Terminal Area Wake Vortex Avoidance.

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Abstract:

The wake vortex transport program has been expanded to include viscous effects and the influence of initial roll-up, atmospheric turbulence, and wind shear on the persistence and motion of wake vortices in terminal areas. Analysis of wake characteristics has shown that changes in the spanwise loading due to flaps increase the initial sink rate, decrease the separation, and initiates the circulation decay process earlier. Buoyancy due to jet exhaust entrainment and ambient stratification retards vortex spreading and increases descent. Atmospheric turbulence and shear promote a more rapid decay reducing the late-time descent and spread rates of vortices. Vortex tilting has been related to an interaction involving the wind shear, ground plane, and the vorticity detrainment process. Recognition of the effects of tilting, spanwise loading, vorticity detrainment, burstsink instabilities, and atmospheric conditions has resulted in an analytic wake transport and decay model with increased accuracy and improved predictive capabilities. Author

Author(s):
Brashears, M. R. ; Zalay, A. D. ; Chou, L. C. ; Shrider, K. R.
Author Organization(s):
LOCKHEED MISSILES AND SPACE CO INC HUNTSVILLE ALA HUNTSVILLE RESEARCH AND ENGINEERING CENTER
Descriptive Note:
Final rept. 11 Feb-10 Oct 75,
Pagination:
0229

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
LMSC-HREC-TR-D496597, FAA-RD-76-94
Contract/Grant Number(s):
DOT-TSC-988
Monitor Series:
76-94, FAA-76-15
 Subject Terms
Communities of Interest:
Air Platforms
Descriptor(s):
*COMMERCIAL AIRCRAFT, *VORTICES, *TRAILING VORTICES, *WAKE, *JET TRANSPORT AIRCRAFT, MATHEMATICAL MODELS, TURBULENCE, ATMOSPHERIC MOTION, MATHEMATICAL PREDICTION, WIND SHEAR, TAKEOFF, METEOROLOGICAL PHENOMENA, AVIATION SAFETY, AIRCRAFT LANDINGS, JET ENGINE EXHAUST
Field(s)/Group(s):
Fluid Mechanics
Keyword(s):
Wake vortex transport, *Wake vortices, Wake vortex avoidance system
Report Date:
1976 May 01