Analysis of the coherent and turbulent stresses of a numerically simulated rough wall pipe

Leon Zen Hsien Chan, M. MacDonald, D. Chung, N. Hutchins, A. Ooi

Research output: Contribution to journalConference article

1 Citation (Scopus)

Abstract

A turbulent rough wall flow in a pipe is simulated using direct numerical simulation (DNS) where the roughness elements consist of explicitly gridded three-dimensional sinusoids. Two groups of simulations were conducted where the roughness semi-amplitude h+ and the roughness wavelength λ+ are systematically varied. The triple decomposition is applied to the velocity to separate the coherent and turbulent components. The coherent or dispersive component arises due to the roughness and depends on the topological features of the surface. The turbulent stress on the other hand, scales with the friction Reynolds number. For the case with the largest roughness wavelength, large secondary flows are observed which are similar to that of duct flows. The occurrence of these large secondary flows is due to the spanwise heterogeneity of the roughness which has a spacing approximately equal to the boundary layer thickness δ.

Original languageEnglish
Article number012011
JournalJournal of Physics: Conference Series
Volume822
Issue number1
DOIs
Publication statusPublished - 11 Apr 2017
Event15th Asian Congress of Fluid Mechanics, ACFM 2016 - Kuching, Sarawak, Malaysia
Duration: 21 Nov 201623 Nov 2016

Fingerprint

roughness
secondary flow
wall flow
boundary layer thickness
sine waves
direct numerical simulation
ducts
wavelengths
Reynolds number
friction
spacing
occurrences
decomposition
simulation

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

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abstract = "A turbulent rough wall flow in a pipe is simulated using direct numerical simulation (DNS) where the roughness elements consist of explicitly gridded three-dimensional sinusoids. Two groups of simulations were conducted where the roughness semi-amplitude h+ and the roughness wavelength λ+ are systematically varied. The triple decomposition is applied to the velocity to separate the coherent and turbulent components. The coherent or dispersive component arises due to the roughness and depends on the topological features of the surface. The turbulent stress on the other hand, scales with the friction Reynolds number. For the case with the largest roughness wavelength, large secondary flows are observed which are similar to that of duct flows. The occurrence of these large secondary flows is due to the spanwise heterogeneity of the roughness which has a spacing approximately equal to the boundary layer thickness δ.",
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Analysis of the coherent and turbulent stresses of a numerically simulated rough wall pipe. / Chan, Leon Zen Hsien; MacDonald, M.; Chung, D.; Hutchins, N.; Ooi, A.

In: Journal of Physics: Conference Series, Vol. 822, No. 1, 012011, 11.04.2017.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Analysis of the coherent and turbulent stresses of a numerically simulated rough wall pipe

AU - Chan, Leon Zen Hsien

AU - MacDonald, M.

AU - Chung, D.

AU - Hutchins, N.

AU - Ooi, A.

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