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On the receptivity and non-parallel stability of travelling disturbances in rotating disk flowThe generation and evolution of small amplitude wavelength traveling disturbances in rotating disk flow is discussed. The steady rotational speed of the disk is perturbed so as to introduce high frequency oscillations in the flow field. Secondly, surface imperfections are introduced on the disk such as roughness elements. The interaction of these two disturbances will generate the instability waves whose evolution is governed by parabolic partial differential equations that are solved numerically. For the class of disturbances considered (wavelength on the order of Reynolds number), it is found that eigensolutions exist which decay or grow algebraically in the radial direction. However, these solutions grow only for frequencies larger than 4.58 times the steady rotational speed of the disk. The computed receptivity coefficient shows that there is an optimum size of roughness for which these modes are excited the most. The width of these roughness elements in the radial direction is about .1 r(sub 0) where r(sub 0) is the radial location of the roughness. It is also found that the receptivity coefficient is larger for a negative spanwise wavenumber than for a positive one. Typical wave angles found for these disturbances are about -26 degrees.
Document ID
19910006683
Document Type
Contractor Report (CR)
Authors
Balakumar, P. (High Technology Corp. Hampton, VA., United States)
Hall, P. (Exeter Univ. (England). Hampton, VA., United States)
Malik, M. R. (High Technology Corp.)
Date Acquired
September 6, 2013
Publication Date
December 1, 1990
Subject Category
AERODYNAMICS
Report/Patent Number
ICASE-90-89
NAS 1.26:187486
AD-A232081
NASA-CR-187486
Funding Number(s)
CONTRACT_GRANT: NAS1-18605
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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