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A rapid-distortion-theory turbulence model for developed unsteady wall-bounded flowA new approach to turbulence modeling in unsteady developed flows has recently been introduced, based on results of rapid distortion theory. The approach involves closing the k-epsilon equations for the organized unsteady component of the flow by modeling local unsteadiness as a rapid distortion of the local structure of the parent turbulent flow, in terms of an effective strain parameter alpha(sub eff). In this paper, the phase-conditioned equations of motion are developed to accommodate a new unsteady dissipation model and local effects of the slow-relaxation time scale of the parent flow. The model equations are tested against measurements of the response of a fully-developed turbulent pipe flow to the superposition of sinusoidal streamwise oscillation. Good agreement is found between measurements and predictions over a wide range of frequencies of unsteadiness, indicating that this approach may be particularly well suited to modeling of unsteady turbulent flows which are perturbations about a well characterized mean.
Document ID
19930023010
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Brereton, G. J. (Michigan Univ. Ann Arbor., United States)
Mankbadi, R. R. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1993
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NAS 1.15:106249
ICOMP-93-22
E-7971
NASA-TM-106249
Accession Number
93N32199
Funding Number(s)
PROJECT: RTOP 505-90-5K
CONTRACT_GRANT: NCC3-233
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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