Laser Doppler Velocimeter Measurements of B-747 Wake Vortex Characteristics.
Final rept. Nov 75-Jan 77,
LOCKHEED MISSILES AND SPACE CO INC HUNTSVILLE ALA HUNTSVILLE RESEARCH AND ENGINEERING CENTER
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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
- Lasers and Masers