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Numerical prediction of flow in slender vorticesThe slender vortex approximation was investigated using the Navier-Stokes equations written in cylindrical coordinates. It is shown that, for free vortices without external pressure gradient, the breakdown length is proportional to the Reynolds number. For free vortices with adverse pressure gradients, the breakdown length is inversely proportional to the value of its gradient. For low Reynolds numbers, the predictions of the simplified system agreed well with the ones obtained from solutions of the full Navier-Stokes equations, whereas for high Reynolds numbers, the flow became quite sensitive to pressure fluctuations; it was found that the failure of the slender vortex equations corresponded to the critical condition as identified by Benjamin (1962) for inviscid flows. The predictions obtained from the approximating system were compared with available experimental results. For low swirl, a good agreement was obtained; for high swirl, on the other hand, upstream effects on the pressure gradient produced by the breakdown bubble caused poor agreement.
Document ID
19880057275
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Reyna, Luis G.
(IBM Thomas J. Watson Research Center Yorktown Heights, NY, United States)
Menne, Stefan
(NASA Langley Research Center Hampton, VA; Aachen, Rheinisch-Westfaelische Technische Hochschule, Federal Republic of Germany, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Computers and Fluids
Volume: 16
Issue: 3, 19
ISSN: 0045-7930
Subject Category
Aerodynamics
Accession Number
88A44502
Distribution Limits
Public
Copyright
Other

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