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Lookup NU author(s): Dr Weichao ShiORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The AuthorsDimpled surfaces have gained increasing attention in recent years for their potential to reduce turbulent skin friction, a capability previously acknowledged for its beneficial implications on heat transfer. As a passive drag reduction method, dimpled surfaces offer significant advantages for marine applications due to their effectiveness and practical applicability. However, despite numerous studies, conflicting opinions and inconsistent drag reduction rates persist in the literature. This paper addresses these ambiguities and offers valuable insights into the effectiveness of dimpled surfaces for drag reduction in fully turbulent flows. We conducted an extensive experimental investigation involving various dimple configurations, including different depth-to-diameter ratios, diameters and orientations, utilising a specialised Fully Turbulent Flow Channel facility and a Particle Image Velocimetry system. Our findings demonstrated that circular dimple geometries, particularly those with low depth ratios, can achieve significant drag reduction of up to 27% as the Reynolds number increases. These results highlight the substantial potential of dimpled surfaces for improving energy efficiency in marine applications, where skin friction accounts for a significant portion of the total drag experienced by large vessels.
Author(s): Ilter YK, Unal UO, Shi W, Tokgoz S, Atlar M
Publication type: Article
Publication status: Published
Journal: Ocean Engineering
Year: 2024
Volume: 307
Print publication date: 01/09/2024
Online publication date: 20/05/2024
Acceptance date: 13/05/2024
Date deposited: 28/05/2024
ISSN (print): 0029-8018
ISSN (electronic): 1873-5258
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.oceaneng.2024.118198
DOI: 10.1016/j.oceaneng.2024.118198
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