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Type: Conference paper
Title: Quadruple decomposition of current-dominated pulsatile rough-wall turbulent pipe flow
Author: Jelly, T.
Chin, R.
Illingworth, S.
Monty, J.
Marusic, I.
Ooi, A.
Citation: 21st Australasian Fluid Mechanics Conference, 2018 / Lau, T., Kelso, R. (ed./s), pp.1-4
Publisher: Australasian Fluid Mechanics Society
Issue Date: 2018
ISBN: 9780646597843
Conference Name: Australasian Fluid Mechanics Conference (10 Dec 2018 - 13 Dec 2018 : Adelaide, Australia)
Statement of
T. O. Jelly, R. C. Chin, S. J. Illingworth, J. P. Monty, L. Marusic and A. S. H. Ooi
Abstract: The physics of pulsatile rough-wall turbulent pipe flow is investigated using data from direct numerical simulation (DNS). Three geometrically-scaled sinusoidal roughness topographies are considered — the amplitude and wavelength of each surface are systematically varied whilst holding their amplitude-towavelength ratio constant. Pulsation is achieved by imposing a time-harmonic axial pressure gradient. The resulting flow-field is triple phase-averaged (in two spatial directions and also in time) which permits a quadruple decomposition of the instantaneous field variables to be invoked. The four components of the quadruple decomposition are: (i) a global-averaged mean component; (ii) a steady roughness-induced fluctuation; (iii) an unsteady pulsation-induced fluctuation and (iv) the remaining turbulent fluctuation. We compare statistics of (i)-(iv) against their non-pulsatile counterpart using past results from related work [1, 2]. Whilst the pulsatile and non-pulsatile data collapse well in the outer region, clear differences are observed in the near-roughness region. In particular, profiles of the mean axial velocity, roughness-induced stress and turbulence-induced stress exhibit consistently lower magnitudes below the roughness crests under pulsatile conditions.
Rights: Commencing with 19AFMC, the Society holds copyright to papers which appear in the Proceedings. Prior to that, copyright resides with authors of the papers.
RMID: 0030107825
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Appears in Collections:Mechanical Engineering conference papers

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