Linear stability analysis and direct numerical simulations of swirling buoyant flows

J. Singh, H. M. Blackburn, J. M. Lopez, A. J. Smits

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The current study investigates the effect of heating defined via Richardson number on the stability of swirling flows via linear stability analysis and direct numerical simulations. Such flows are common in combustion and mixing applications and are simple models for atmospheric flows such as fire whirls and dust devils. The linear stability characteristics of azimuthal wavenumbers m = 1-5 are investigated at a fixed Reynolds number of 500 and at three inlet swirl angles where the non-buoyant (without heating) flow shows linear stability characteristics different from each other. The results show that the heating may initially have a stabilising effect but with more heating, the flow ultimately becomes unstable to perturbations. The growth rate of the leading eigenmode agrees with the predictions of three-dimensional direct numerical simulations. The centre-line axial velocity is increased noticeably with heating, indicating much larger axial momentum in unstable buoyant flows than non-buoyant flows.

Original languageEnglish (US)
Title of host publicationProceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018
EditorsTimothy C.W. Lau, Richard M. Kelso
PublisherAustralasian Fluid Mechanics Society
ISBN (Electronic)9780646597843
StatePublished - 2018
Event21st Australasian Fluid Mechanics Conference, AFMC 2018 - Adelaide, Australia
Duration: Dec 10 2018Dec 13 2018

Publication series

NameProceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018

Conference

Conference21st Australasian Fluid Mechanics Conference, AFMC 2018
CountryAustralia
CityAdelaide
Period12/10/1812/13/18

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

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