Please use this identifier to cite or link to this item: http://dx.doi.org/10.14279/depositonce-8175
Main Title: The interaction between a spatially oscillating jet emitted by a fluidic oscillator and a cross-flow
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: This experimental study investigates the fundamental flow field of a spatially oscillating jet emitted by a fluidic oscillator into an attached cross-flow. Dominant flow structures, such as the jet trajectory and dynamics of streamwise vortices, are discussed in detail with the aim of understanding the interaction between the spatially oscillating jet and the cross-flow. The oscillating jet is ejected perpendicular to the cross-flow. A moveable stereoscopic particle image velocimetry (PIV) system is employed for the plane-by-plane acquisition of the flow field. The three-dimensional, time-resolved flow field is obtained by phase averaging the PIV results based on a pressure signal from inside the fluidic oscillator. The influence of velocity ratio and Strouhal number is assessed. Compared to a common steady wall-normal jet, the spatially oscillating jet penetrates to a lesser extent into the cross-flow’s wall-normal direction in favour of a considerable spanwise penetration. The flow field is dominated by streamwise-oriented vortices, which are convected downstream at the speed of the cross-flow. The vortex dynamics exhibits a strong dependence on the Strouhal number. For small Strouhal numbers, the spatially oscillating jet acts similar to a vortex-generating jet with a time-dependent deflection angle. Accordingly, it forms time-dependent streamwise vortices. For higher Strouhal numbers, the cross-flow is not able to follow the motion of the jet, which results in a quasi-steady wake that forms downstream of the jet. The results suggest that the flow field approaches a quasi-steady behaviour when further increasing the Strouhal number.
URI: https://depositonce.tu-berlin.de//handle/11303/9074
http://dx.doi.org/10.14279/depositonce-8175
Issue Date: 2019
Date Available: 7-Feb-2019
DDC Class: 532 Mechanik der Fluide, Mechanik der Flüssigkeiten
Subject(s): fluid oscillator
jets
flow field
cross-flow
fluidischer Oszillator
Sponsor/Funder: DFG, 289230680, Die Interaktion zwischen einem räumlich oszillierenden Strahl und einer Querströmung
License: http://rightsstatements.org/vocab/InC/1.0/
Journal Title: Journal of fluid mechanics
Publisher: Cambridge University Press
Publisher Place: Cambridge
Volume: 863
Publisher DOI: 10.1017/jfm.2018.981
Page Start: 215
Page End: 241
EISSN: 1469-7645
ISSN: 0022-1120
Appears in Collections:FG Experimentelle Strömungsmechanik » Publications

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