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A three-dimensional viscous flow analysis for the helicopter tip vortex generation problemThe tip vortex flow field occurring in the vicinity of the tip region of a a helicopter rotor blade is a very complicated three-dimensional, viscous flow phenomenon. The details of the flow in the tip region can have a major effect in determining the generated rotor noise and can significantly affect the performance and dynamic loading of the rotor blade. The three-dimensional viscous subsonic tip vortex generation processes is investigated by a numerical procedure which allows spatial forward-marching integration, utilizing flow approximations from the velocity-decomposition approach of Briley and McDonald. The approach has been applied to compute the laminar and turbulent tip vortex flows for a constant thickness slab airfoil with a square tip, a constant thickness slab airfoil with a half round tip and a NACA 0012 airfoil with a half round tip. The basic mechanism of the tip vortex generation process as well as the prediction of vortex appearance, strength and secondary flow shown by the calculations are in qualitative agreement with experimental results.
Document ID
19850025801
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Lin, S. J. (Scientific Research Associates, Inc. Glastonbury, CT, United States)
Levy, R. (Scientific Research Associates, Inc. Glastonbury, CT, United States)
Shamroth, S. J. (Scientific Research Associates, Inc. Glastonbury, CT, United States)
Govindan, T. R. (Scientific Research Associates, Inc. Glastonbury, CT, United States)
Date Acquired
September 5, 2013
Publication Date
August 1, 1985
Publication Information
Publisher: NASA
Subject Category
Aerodynamics
Report/Patent Number
NASA-CR-3906
NAS 1.26:3906
Accession Number
85N34114
Funding Number(s)
CONTRACT_GRANT: NAS1-14904
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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