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Main Title: Phase-Averaging Methods for the Natural Flowfield of a Fluidic Oscillator
Author(s): Ostermann, Florian
Woszidlo, Rene
Nayeri, Christian Navid
Paschereit, Christian Oliver
Type: Article
Language Code: en
Is Part Of: 10.14279/depositonce-7144
Abstract: The presented study examines various methods for phase averaging the naturally oscillating flowfield of a scaled-up fluidic oscillator. No external trigger is employed to control the oscillation of the flow. Mathematical and signal conditioning approaches for phase averaging the data are categorized and described. The results of these methods are evaluated for their accuracy in capturing the natural flowfield. The respective criteria are based on the minimum fluctuation in oscillation period length, the conservation of velocity amplitudes, and the number of snapshots per phase-averaging window. Although all methods produce reasonable qualitative results, only two methods are identified to provide the desired quantitative accuracy and suitability for the investigated flowfield. The first method is based on conditioning a time-resolved pressure signal from the feedback channels in the oscillator. An autocorrelation applied to the reference signal improves the period identification. The second method employs a mathematical approach by means of proper orthogonal decomposition. Because the conventional use of proper orthogonal decomposition reveals shortcomings in quantitative accuracy, it is modified by imposing an even distribution of snapshots per phase angle window. The results demonstrate the feasibility and improved accuracy of the modified proper orthogonal decomposition. Therefore, accurate phase averaging can be conducted without the need for a time-resolved reference signal.
Issue Date: 2015
Date Available: 7-Feb-2019
DDC Class: 532 Mechanik der Fluide, Mechanik der Flüssigkeiten
Subject(s): phase-averaging methods
fluid oscillator
signal conditioning methods
mathematical methods
Journal Title: AIAA journal
Publisher: American Institute of Aeronautics and Astronautics
Publisher Place: Reston, VA.
Volume: 53
Issue: 8
Publisher DOI: 10.2514/1.J053717
Page Start: 2359
Page End: 2368
EISSN: 1533-385X
ISSN: 0001-1452
Appears in Collections:FG Experimentelle Strömungsmechanik » Publications

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