Disturbance evolution in rotating boundary layers

Christian Thomas, Christopher Davies

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Abstract

The global linear stability of the family of rotating boundary layers (that includes discs and cones) is reviewed. Using a velocity-vorticity form of the linearised Navier-Stokes equations, disturbance evolution is impulsively excited for a variety of flow geometries and perturbation parameter settings. For azimuthal mode numbers below a fixed threshold value, disturbance development is dominated by convectively unstable characteristics, even though the flow might be locally absolutely unstable. As the azimuthal mode number is increased to larger values a form of global linear instability emerges that is characterised by a faster than exponential temporal growth. However, this is only observed when the azimuthal mode number is taken to be significantly greater than the conditions necessary for the onset of absolute instability to occur.

Original languageEnglish
Title of host publicationProceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018
EditorsTimothy C.W. Lau, Richard M. Kelso
Place of PublicationAdelaide SA Australia
PublisherAustralasian Fluid Mechanics Society
Number of pages4
ISBN (Electronic)9780646597843
Publication statusPublished - 13 Dec 2018
EventAustralasian Fluid Mechanics Conference 2018 - Adelaide Convention Centre, Adelaide, Australia
Duration: 10 Dec 201813 Dec 2018
Conference number: 21st
https://aomevents.eventsair.com/QuickEventWebsitePortal/21st-australasian-fluid-mechanics-conference/afmc2018

Conference

ConferenceAustralasian Fluid Mechanics Conference 2018
Abbreviated titleAFMC 2018
CountryAustralia
CityAdelaide
Period10/12/1813/12/18
Internet address

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