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Detection, Tracking and Analysis of Turbulent Spots and Other Coherent Structures in Unsteady TransitionTransition on turbine blades is an important factor in the determination of eventual flow separation and engine performance. The phenomenon is strongly affected by unsteady flow conditions (wake passing). It is likely that some physics of unsteadiness should be included in advanced models, but it is unclear which properties would best embody this information. In this paper, we use a GEAE experimental database in unsteady transition to test some tools of spot identification, tracking and characterization. In this preliminary study, we identify some parameters that appear to be insensitive to wake passing effects, such as convection speed, and others more likely to require unsteady modeling. The main findings are that wavelet duration can be used as a measure of spot size, and that spot energy density is most closely correlated to the wake passing. The energy density is also correlated to spot size, but spot size appears unrelated to the phase angle. Recommendations are made for further study.
Document ID
20010016109
Acquisition Source
Glenn Research Center
Document Type
Contractor Report (CR)
Authors
Lewalle, Jacques (Syracuse Univ. NY United States)
Ashpis, David
Date Acquired
September 7, 2013
Publication Date
December 1, 2000
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
NASA/CR-2000-210694
NAS 1.26:210694
E-12622
Funding Number(s)
CONTRACT_GRANT: NASA Order C-76220-D
PROJECT: RTOP 523-26-33
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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