Conference Proceedings

An experimental investigation into the breakdown of riblet drag reduction at post-optimal conditions

R Newton, D Chung, N Hutchins

Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 | Published : 2018

Abstract

© 2018 Australasian Fluid Mechanics Society. All rights reserved. A long-standing question in riblet research is why drag reduction only occurs within a small, non-dimensionally scaled envelope, outside of which drag is significantly increased. For riblets with viscous-scaled spacings that are much larger than those required for drag reduction, one hypothesis is that the riblets exhibit k-type, ‘fully rough’ behaviour. However, this seems counter-intuitive since fully rough behaviour is typically associated with a dominance of pressure drag over viscous drag, and yet riblets can sustain no pressure drag. This study aims to investigate this issue by conducting single normal hot-wire traverses..

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