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Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements

He, Chuangxin; Liu, Yingzheng; Gan, Lian

Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements Thumbnail


Authors

Chuangxin He

Yingzheng Liu



Abstract

This study focuses on the dynamics of the three-dimensional jet flow issued from a lobed nozzle. Flow field measurements were performed using a split-screen dual-camera tomographic particle image velocimetry (tomo-PIV) system. The lobed nozzle was constructed using three-circle configuration at the nozzle exit, where the ratio of the circular centre offset to the circle radius was a⁄b= 0.8. Two high-speed cameras were used with an appropriate combination of prismatic and planar mirrors to split each camera into two views. The Reynolds number was fixed at Re= 2400, and the circular jet at the same Reynolds number was also measured for comparison. Fourier mode decomposition was used to identify the large-scale structures superposed in the unsteady flow field. The lobe trough in the jet decreased the jet’s width due to the smooth connection between the pipe section and the lobed exit. Turbulence was intensified in the jet shear layer, and the passing fluid puffs in the circular jet instantaneous flow field were also broken in the lobed jet. The successively passing fluid puffs in the circular jet were observed to be the axisymmetric large-scale structure in Fourier modes dominating at St= 0.39. However, breakdown of the axisymmetric structures was induced by the lobed nozzle at St= 0.51 and 0.65, and the double helical modes arose at St= 0.28 and 0.38 (also 0.4) in the shear layer of the jet potential core and interacted with the entire jet column.

Citation

He, C., Liu, Y., & Gan, L. (2021). Dynamics of the Jet Flow Issued from a Lobed Nozzle: Tomographic Particle Image Velocimetry Measurements. International Journal of Heat and Fluid Flow, 89, Article 108795. https://doi.org/10.1016/j.ijheatfluidflow.2021.108795

Journal Article Type Article
Acceptance Date Feb 22, 2021
Online Publication Date Mar 4, 2021
Publication Date 2021-06
Deposit Date Feb 26, 2021
Publicly Available Date Mar 28, 2024
Journal International Journal of Heat and Fluid Flow
Print ISSN 0142-727X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 89
Article Number 108795
DOI https://doi.org/10.1016/j.ijheatfluidflow.2021.108795

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