Show simple item record

dc.contributor.authorRouhi, A
dc.contributor.authorChung, D
dc.contributor.authorHutchins, N
dc.contributor.editorOrlu, R
dc.contributor.editorTalamelli, A
dc.contributor.editorPeinke, J
dc.contributor.editorOberlack, M
dc.date.accessioned2020-12-09T23:38:04Z
dc.date.available2020-12-09T23:38:04Z
dc.date.issued2019
dc.identifier.citationRouhi, A., Chung, D. & Hutchins, N. (2019). Roughness and Reynolds Number Effects on the Flow Past a Rough-to-Smooth Step Change. Orlu, R (Ed.) Talamelli, A (Ed.) Peinke, J (Ed.) Oberlack, M (Ed.) iTi 2018: Progress in Turbulence VIII, 226, pp.81-86. Springer International Publishing. https://doi.org/10.1007/978-3-030-22196-6_13.
dc.identifier.isbn9783030221959
dc.identifier.issn0930-8989
dc.identifier.urihttp://hdl.handle.net/11343/253283
dc.description.abstractWe report direct numerical simulations (DNSs) of open-channel flow with a step change from three-dimensional sinusoidal rough surface to smooth surface. We investigate the persistence of non-equilibrium behaviour beyond this step change (i.e. departures from the equilibrium smooth open-channel flow) and how this depends on (1) roughness virtual origin ϵ/hϵ/h? (scaled by the channel height h), (2) roughness size k / h?, (3) roughness shape? and (4) Reynolds number ReτReτ? To study (1), the roughness origin was placed aligned with, below (step-up) and above (step-down) the smooth patch. To study (2), the equivalent sand-grain roughness of the aligned case was decreased from k+s≃ks+≃ 160 to k+s≃106ks+≃106. To study (3) and (4) the step-down case at Reτ≃395Reτ≃395 was compared with a backward-facing step case at Reτ≃527Reτ≃527, and DNS of square rib rough-to-smooth case at Reτ≃1160Reτ≃1160 (Ismail et al., J. Fluid Mech., vol. 843, 2018, pp. 419–449). Results showed that ϵ/hϵ/h affects the departure from equilibrium by a large extent, while k / h, roughness shape and ReτReτ have a marginal influence. The departure from equilibrium was found to be related to the near-wall amplification of Reynolds shear stress, which in turn depends on ϵ/hϵ/h, i.e. higher ϵ/hϵ/h leads to higher amplification.
dc.languageEnglish
dc.publisherSpringer International Publishing
dc.sourceiTi Conference on Turbulence
dc.titleRoughness and Reynolds Number Effects on the Flow Past a Rough-to-Smooth Step Change
dc.typeConference Paper
dc.identifier.doi10.1007/978-3-030-22196-6_13
melbourne.affiliation.departmentMechanical Engineering
melbourne.source.titleSpringer Proceedings in Physics
melbourne.source.volume226
melbourne.source.pages81-86
melbourne.identifier.arcDP160102279
melbourne.elementsid1414872
pubs.publisher-urlhttps://link.springer.com/chapter/10.1007%2F978-3-030-22196-6_13
melbourne.contributor.authorRouhi, Amirreza
melbourne.contributor.authorHutchins, Nicholas
melbourne.contributor.authorChung, Daniel
dc.identifier.eissn1867-4941
melbourne.identifier.fundernameidAustralian Research Council, DP160102279
melbourne.event.locationBertinoro, Italy
melbourne.accessrightsOpen Access


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record