On the Mechanism of Drag Reduction in Fully-Developed Turbulent Channel Flow with a Streamwise Micro-featured Superhydrophobic Wall

The superhydrophobic drag reduction changes the structures of turbulent flow. However, the underlying mechanism is not clear. The aim of this study is to determine the alternations of turbulent flow due to applying a streamwise micro-featured superhydrophobic wall. Large eddy simulations are perform...

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Bibliographic Details
Published in:Journal of Applied Fluid Mechanics 2017-09, Vol.10 (5), p.1363-1374
Main Authors: Saadat-Bakhsh, M., Nouri, N. M., Norouzi, H.
Format: Article
Language:English
Subjects:
Alternations
Channel flow
Drag reduction
Fluid dynamics
Fluid flow
Hydrophobic surfaces
Hydrophobicity
Large eddy simulation
Low speed
Reynolds stress
Superhydrophobic surface
Drag reduction mechanism
Coherent structures
Streak strength
Turbulent flow
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Summary:The superhydrophobic drag reduction changes the structures of turbulent flow. However, the underlying mechanism is not clear. The aim of this study is to determine the alternations of turbulent flow due to applying a streamwise micro-featured superhydrophobic wall. Large eddy simulations are performed to explore the effect of micro-features on near-wall behaviors. The results indicate that the outward motion of the lifted low-speed streaks is restricted to the lower wall layers, and the region of maximum production of streamwise vorticities is shifted toward the micro-featured wall. The quadrant analysis of Reynolds stress shows that there is a stronger increase in outward motion of high-speed fluid and inward motion of low-speed fluid than ejection and sweep.
ISSN:1735-3572
1735-3645
DOI:10.18869/acadpub.jafm.73.242.27724