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dc.contributor.authorSkeide, Arne Kilvik
dc.contributor.authorBardal, Lars Morten
dc.contributor.authorOggiano, Luca
dc.contributor.authorHearst, R. Jason
dc.description.abstractThe impact of flow-normal ribs and small-scale surface roughness on the drag and vortex shedding of a circular cylinder was investigated. Three rib heights, four relative rib spacings and three different forms of microroughness were combined to produce 28 unique surface coatings for the cylinder. The drag was measured in a wind tunnel for Reynolds numbers in the range 20; 000 < Re < 160; 000, representing nearly a decade change centred about the drag crisis. The drag measurements were complemented by hot-wire measurements in the wake to investigate the vortex shedding frequency. The results show significant average drag reduction, up to 23%, for most of the ribbed geometries compared to a smooth cylinder for Re < 160; 000. Increasing the rib height was found to reduce the critical Reynolds number and increase the minimum drag coefficient. Varying the rib spacing resulted in an ‘‘optimal” spacing, approximately five times the rib height, that caused the lowest critical Reynolds number. Increasing the micro-roughness resulted in a reduction in the critical Reynolds number and an increase in the minimum drag coefficient.en_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleThe significant impact of ribs and small-scale roughness on cylinder drag crisisen_US
dc.typePeer revieweden_US
dc.typeJournal articleen_US
dc.source.journalJournal of Wind Engineering and Industrial Aerodynamicsen_US
dc.description.localcode© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal