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Effect of ground and/or ceiling planes on thrust of rotors in hoverThe thrust produced by a helicopter rotor hovering near ground and/or ceiling planes is investigated experimentally and theoretically. In the experiment, the thrust was measured on a 0.324-m-diam rotor operating between floor and ceiling planes which were located from 6 to 0.08 diam from the rotor disk. In the first theoretical model studied, the incompressible and inviscid flow induced by a sequence of vortex cylinders, located above and below the rotor to simulate the rotor wake and its interaction with the floor and ceiling planes, was considered. Comparison with experiment showed that this model overpredicts the change in thrust caused by the proximity of the walls. Therefore, a second arrangement of vortex cylinders was introduced which provides a more accurate prediction of the ground and ceiling effects on the thrust of the rotor in hover. The applicability of these results to a vented wind tunnel is also discussed.
Document ID
19850022701
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Rossow, V. J.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 5, 2013
Publication Date
July 1, 1985
Subject Category
Aerodynamics
Report/Patent Number
NAS 1.15:86754
REPT-85256
NASA-TM-86754
Accession Number
85N31014
Funding Number(s)
PROJECT: RTOP 505-31-21
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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