Small-scale behavior in distorted turbulent boundary layers at low Reynolds number

Saddoughi, Seyed G.

During the last three years we have conducted high- and low-Reynolds-number experiments, including hot-wire measurements of the velocity fluctuations, in the test-section-ceiling boundary layer of the 80- by 120-foot Full-Scale Aerodynamics Facility at NASA Ames Research Center, to test the local-isotropy predictions of Kolmogorov's universal equilibrium theory. This hypothesis, which states that at sufficiently high Reynolds numbers the small-scale structures of turbulent motions are independent of large-scale structures and mean deformations, has been used in theoretical studies of turbulence and computational methods such as large-eddy simulation; however, its range of validity in shear flows has been a subject of controversy. The present experiments were planned to enhance our understanding of the local-isotropy hypothesis. Our experiments were divided into two sets. First, measurements were taken at different Reynolds numbers in a plane boundary layer, which is a 'simple' shear flow. Second, experiments were designed to address this question: will our criteria for the existence of local isotropy hold for 'complex' nonequilibrium flows in which extra rates of mean strain are added to the basic mean shear?

Document ID

19950016039

Acquisition Source

Legacy CDMS

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Other

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Date Acquired

September 6, 2013

Publication Date

December 1, 1994

Publication Information

Publication: Annual Research Briefs, 1994

Subject Category

Accession Number

95N22456

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Public

Work of the US Gov. Public Use Permitted.

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