Accession Number:

ADA048275

Title:

Laser Doppler Velocimeter Measurements of B-747 Wake Vortex Characteristics.

Descriptive Note:

Final rept. Nov 75-Jan 77,

Corporate Author:

LOCKHEED MISSILES AND SPACE CO INC HUNTSVILLE ALA HUNTSVILLE RESEARCH AND ENGINEERING CENTER

Personal Author(s):

• Brashears,M. R.
• Zalay,A. D.

Report Date:

1977-09-01

Pagination or Media Count:

220.0

Abstract:

To determine the behavior of the wake vortices of a B-747 at low altitudes and to measure the vortex-decay process behind the B-747 as a function of altitude above ground, flap and spoiler settings, and different flight configurations, a B-747 aircraft flew 54 passes at low level over a ground-based laser Doppler velocimeter LDV system. From the LDV measurements, the location and flow field of the wake vortices and the general vortex roll-up, transport, and decay trends were obtained. Results of the study indicated that the deployment of spoilers and flaps enhanced the decay of the vortex peak tangential velocity in the near wake while aircraft altitude, glide slope, and landing gear deployment had little effect. The report discusses the LDV wake vortex measurements including the instrumentation used, the experimental test sequence, the results of the wake measurements in terms of the vortex roll-up, transport, and decay trends, and a comparison of the wake vortex characteristics for different configurations. Author

Descriptors:

• *AVIATION SAFETY
• *TRANSPORT AIRCRAFT
• *LASER VELOCIMETERS
• *VORTEX GENERATORS
• *WAKE DETECTORS
• LIFE EXPECTANCY(SERVICE LIFE)
• AERODYNAMIC STABILITY
• WIND
• FLAPS(CONTROL SURFACES)
• SEPARATION
• DECAY
• SPOILERS
• LOW ALTITUDE
• LANDING GEAR
• DOPPLER EFFECT
• GLIDE SLOPE

Subject Categories:

• Aerodynamics
• Lasers and Masers

Distribution Statement:

APPROVED FOR PUBLIC RELEASE