Busse, A. and Zhdanov, O. (2022) Direct numerical simulations of turbulent channel flow over ratchet roughness. Flow, Turbulence and Combustion, 109(4), pp. 1195-1213. (doi: 10.1007/s10494-022-00352-8)
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Abstract
The influence of the orientation of ratchet-type rough surfaces on their fluid dynamic roughness effect is investigated using direct numerical simulations of turbulent channel flow at Reτ= 395. The ratchet length-to-height ratio is varied from ℓ/ k= 2 to 16 for a fixed ratchet height of k/ δ= 0.1 where δ is the mean channel half-height. The results show that both roughness function and mean flow and turbulence statistics strongly depend on the ratchet orientation. Existing empirical formulae, which estimate the roughness function Δ U+ or the equivalent sand-grain roughness ks based on surface-slope related parameters such as the effective slope or the Sigal-Danberg parameter, fail to accurately predict the differences between ratchet surfaces with high windward slopes and ratchet surfaces with high leeward slopes.
Item Type: | Articles |
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Additional Information: | We gratefully acknowledge support by the Engineering and Physical Sciences Research Council under grant numbers EP/V002066/1 and EP/P009875/1, and access to the HPC facility Cirrus hosted by EPCC Edinburgh under the ‘Access to HPC’ scheme. A.B. gratefully acknowledges support via a Leverhulme Trust Research Fellowship. |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Busse, Professor Angela and Zhdanov, Dr Oleksandr |
Authors: | Busse, A., and Zhdanov, O. |
College/School: | College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity |
Journal Name: | Flow, Turbulence and Combustion |
Publisher: | Springer |
ISSN: | 1386-6184 |
ISSN (Online): | 1573-1987 |
Published Online: | 09 August 2022 |
Copyright Holders: | Copyright © 2022 The Authors |
First Published: | First published in Flow, Turbulence and Combustion 109(4): 1195-1213 |
Publisher Policy: | Reproduced under a Creative Commons License |
Data DOI: | 10.5525/gla.researchdata.1318 |
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