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On the stability of von Kármán rotating-disk boundary layers with radial anisotropic surface roughness

journal contribution
posted on 25.02.2016, 13:21 by Stephen J. Garrett, A. J. Cooper, J. H. Harris, M. Ozkan, A. Segalini, P. J. Thomas
We summarise results of a theoretical study investigating the distinct convective instability properties of steady boundary-layer flow over rough rotating disks. A generic roughness pattern of concentric circles with sinusoidal surface undulations in the radial direction is considered. The goal is to compare predictions obtained by means of two alternative, and fundamentally different, modelling approaches for surface roughness for the first time. The motivating rationale is to identify commonalities and isolate results that might potentially represent artefacts associated with the particular methodologies underlying one of the two modelling approaches. The most significant result of practical relevance obtained is that both approaches predict overall stabilising effects on type I instability mode of rotating disk flow. This mode leads to transition of the rotating-disk boundary layer and, more generally, the transition of boundary-layers with a cross-flow profile. Stabilisation of the type 1 mode means that it may be possible to exploit surface roughness for laminar-flow control in boundary layers with a cross-flow component. However, we also find differences between the two sets of model predictions, some subtle and some substantial. These will represent criteria for establishing which of the two alternative approaches is more suitable to correctly describe experimental data when these become available.

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Citation

Physics of Fluids, 2016, 28, 014104

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Mathematics

Version

VoR (Version of Record)

Published in

Physics of Fluids

Publisher

American Institute of Physics (AIP)

issn

1070-6631

eissn

1089-7666

Acceptance date

21/12/2015

Copyright date

2016

Available date

25/02/2016

Publisher version

http://scitation.aip.org/content/aip/journal/pof2/28/1/10.1063/1.4939793

Language

en

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