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A study of the temporal stability of multiple cell vorticesThe effect of initial mean velocity field on the stability characteristics of longitudinal vortices is documented in detail. The temporal stability of isolated multiple cell vortices is considered. The types of vortices studied include single cell as well as two and three cell vortices. It is shown that cell multiplicity in the vortex core has drastic effects on the stability characteristics. On the basis of numerical calculations, it is concluded that the growth rates of instabilities in multiple cell vortices are substantially larger (two to threefold increases are observed) than those of a single cell vortex. It is also determined that there is a substantial increase in the effective range of axial and azimuthal wavenumbers where instabilities are present. But most importantly, there is the appearance of a variety of viscous modes of instability. In the case of vortices, these latter instabilities which highlight the importance of viscous forces have never been reported before. These effects are discussed in detail for the case of a two cell vortex.
Document ID
19900002652
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Khorrami, Mehdi R. (Old Dominion Univ. Norfolk, VA, United States)
Date Acquired
September 6, 2013
Publication Date
November 1, 1989
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NASA-CR-4261
NAS 1.26:4261
Accession Number
90N11968
Funding Number(s)
PROJECT: RTOP 505-60-31-07
CONTRACT_GRANT: NAG1-530
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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