Zhdanov, O. , Jelly, T. O. and Busse, A. (2024) Influence of ridge spacing, ridge width, and Reynolds number on secondary currents in turbulent channel flow over triangular ridges. Flow, Turbulence and Combustion, 112, pp. 105-128. (doi: 10.1007/s10494-023-00488-1)
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Abstract
Most studies of secondary currents (SCs) over streamwise aligned ridges have been performed for rectangular ridge cross-sections. In this study, secondary currents above triangular ridges are systematically studied using direct numerical simulations of turbulent channel flow. The influence of ridge spacing on flow topology, mean flow, and turbulence statistics is investigated at two friction Reynolds numbers, 550 and 1000. In addition, the effects of ridge width on SCs, which have not previously been considered for this ridge shape, are explored. The influence of SCs on shear stress statistics increases with increased ridge spacing until SCs fill the entire channel. One of the primary findings is that, for ridge configurations with pronounced secondary currents, shear stress statistics exhibit clear Reynolds number sensitivity with a significant growth of dispersive shear stress levels with Reynolds number. In contrast to rectangular ridges, no above-ridge tertiary flows are observed for the tested range of ridge widths. Flow visualisations of SCs reveal the existence of corner vortices that form at the intersection of the lateral ridge sides and the smooth-wall sections. These are found to gradually disappear as ridges increase in width. Premultiplied spectra of streamwise velocity fluctuations show strong dependency on the spanwise sampling location. Whereas spanwise averaged spectra show no strong modifications by SCs, a significant increase of energy levels emerges at higher wavelengths for spectra sampled at the spanwise locations that correspond to the centres of the secondary currents.
| Item Type: | Articles |
|---|---|
| Additional Information: | Funding We gratefully acknowledge support for this work by the United Kingdom’s Engineering and Physical Sciences Research Council under grant number EP/V002066/1. |
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Busse, Professor Angela and Jelly, Mr Thomas and Zhdanov, Dr Oleksandr |
| Creator Roles: | Zhdanov, O.Conceptualization, Methodology, Investigation, Formal analysis, Data curation, Writing – original draft, Writing – review and editing, Visualization Jelly, T.Formal analysis, Writing – review and editing Busse, A.Conceptualization, Methodology, Resources, Writing – review and editing, Supervision, Project administration, Funding acquisition |
| Authors: | Zhdanov, O., Jelly, T. O., and Busse, A. |
| College/School: | College of Science and Engineering > School of Engineering College of Science and Engineering > School of Engineering > Systems Power and Energy |
| Journal Name: | Flow, Turbulence and Combustion |
| Publisher: | Springer |
| ISSN: | 1386-6184 |
| ISSN (Online): | 1573-1987 |
| Published Online: | 26 September 2023 |
| Copyright Holders: | Copyright © The Author(s) 2023 |
| First Published: | First published in Flow, Turbulence and Combustion 112: 105–128 |
| Publisher Policy: | Reproduced under a Creative Commons License |
| Data DOI: | 10.5525/gla.researchdata.1493 |
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