NTRS - NASA Technical Reports Server

Back to Results
Wavelet Analysis of Turbulent Spots and Other Coherent Structures in Unsteady TransitionThis is a secondary analysis of a portion of the Halstead data. The hot-film traces from an embedded stage of a low pressure turbine have been extensively analyzed by Halstead et al. In this project, wavelet analysis is used to develop the quantitative characterization of individual coherent structures in terms of size, amplitude, phase, convection speed, etc., as well as phase-averaged time scales. The purposes of the study are (1) to extract information about turbulent time scales for comparison with unsteady model results (e.g. k/epsilon). Phase-averaged maps of dominant time scales will be presented; and (2) to evaluate any differences between wake-induced and natural spots that might affect model performance. Preliminary results, subject to verification with data at higher frequency resolution, indicate that spot properties are independent of their phase relative to the wake footprints: therefore requirements for the physical content of models are kept relatively simple. Incidentally, we also observed that spot substructures can be traced over several stations; further study will examine their possible impact.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Lewalle, Jacques
(Syracuse Univ. NY United States)
Date Acquired
August 18, 2013
Publication Date
June 1, 1998
Publication Information
Publication: Minnowbrook II 1997 Workshop on Boundary Layer Transition in Turbomachines
Subject Category
Fluid Mechanics And Heat Transfer
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available