Accession Number:

AD0752628

Title:

Helicopter Rotor Wake Geometry and Airloads and Helicopter Rotor Wakes

Descriptive Note:

Final scientific technical rept. 6 Jun 1971-6 Jun 1972

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE AEROPHYSICS LAB

Personal Author(s):

• Scully, M. P.
• Sullivan, J. P.

Report Date:

1972-08-01

Pagination or Media Count:

67.0

Abstract:

Computer programs have been developed for the calculation of helicopter rotor tip vortex geometry in hover and forward flight and for the calculation of helicopter rotor harmonic airloads in forward flight. Calculated forward flight tip vortex geometries compare well in general with experimental smoke studies although there are differences in detail. The hovering tip vortex geometry agrees qualitatively with experiment but does not move downward fast enough. Airloads were computed using both the classical rigid wake assumption and the distorted tip vortex geometry obtained from the computer program. When compared with experimental airloads measurements the rigid wake airloads give better results than the distorted wake airloads.

Descriptors:

• *FLOWMETERS
• *HELICOPTER ROTORS
• AERODYNAMIC LOADING
• DOPPLER EFFECT
• FLOW FIELDS
• FLOW VISUALIZATION
• HOVERING
• LASERS
• VORTICES
• WAKE

Subject Categories:

• Helicopters
• Test Facilities, Equipment and Methods
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE