On the stability of von Kármán rotating-disk boundary layers with radial anisotropic surface roughness
2016 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 28, no 1, 014104Article in journal (Refereed) PublishedText
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. © 2016 AIP Publishing LLC.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2016. Vol. 28, no 1, 014104
Boundary layer flow, Boundary layers, Forecasting, Laminar boundary layer, Laminar flow, Surface roughness, Anisotropic surfaces, Concentric circles, Convective instabilities, Instability modes, Rotating disk flow, Roughness patterns, Sinusoidal surfaces, Theoretical study, Rotating disks
IdentifiersURN: urn:nbn:se:kth:diva-186752DOI: 10.1063/1.4939793ScopusID: 2-s2.0-84955494783OAI: oai:DiVA.org:kth-186752DiVA: diva2:929916
QC 201605202016-05-202016-05-132016-05-20Bibliographically approved