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Main Title: The time-resolved natural flow field of a fluidic oscillator
Author(s): Woszidlo, Rene
Ostermann, Florian
Nayeri, Christian Navid
Paschereit, Christian Oliver
Type: Article
Language Code: en
Is Part Of: 10.14279/depositonce-7144
Abstract: The internal and external flow field of a fluidic oscillator with two feedback channels are examined experimentally within the incompressible flow regime. A scaled-up device with a square outlet nozzle is supplied with pressurized air and emits a spatially oscillating jet into quiescent environment. Time-resolved information are obtained by phase-averaging pressure and PIV data based on an internal reference signal. The temporal resolution is better than a phase angle of 3°. A detailed analysis of the internal dynamics reveals that the oscillation mechanism is based on fluid feeding into a separation bubble between the jet and mixing chamber wall which pushes the jet to the opposite side. The total volume of fluid transported through one feedback channel during one oscillation cycle matches the total growth of the separation bubble from its initial size to its maximum extent. Although the oscillation frequency increases linearly with supply rate, sudden changes in the internal dynamics are observed. These changes are caused by a growth in reversed flow through the feedback channels. The time-resolved properties of the emitted jet such as instantaneous jet width and exit velocity are found to oscillate substantially during one oscillation cycle. Furthermore, the results infer that the jet’s oscillation pattern is approximately sinusoidal with comparable residence and switching times.
Issue Date: 2015
Date Available: 7-Feb-2019
DDC Class: 532 Mechanik der Fluide, Mechanik der Flüssigkeiten
Subject(s): particle image velocimetry
proper orthogonal decomposition
deflection angle
separation bubble
supply rate
Journal Title: Experiments in fluids
Publisher: Springer
Publisher Place: Heidelberg
Volume: 56
Issue: 6
Article Number: 125
Publisher DOI: 10.1007/s00348-015-1993-8
EISSN: 1432-1114
ISSN: 0723-4864
Appears in Collections:FG Experimentelle Strömungsmechanik » Publications

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