A fast direct numerical simulation method for characterising hydraulic roughness

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

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

We describe a fast direct numerical simulation (DNS) method that promises to di- rectly characterise the hydraulic roughness of any given rough surface, from the hy- draulically smooth to the fully rough regime. The method circumvents the unfavourable computational cost associated with simulating high-Reynolds-number flows by employ- ing minimal-span channels (Jiḿenez & Moin 1991). Proof-of-concept simulations demon- strate that flows in minimal-span channels are sufficient for capturing the downward velocity shift, that is, the Hama roughness function, predicted by flows in full-span chan- nels. We consider two sets of simulations, first with modelled roughness imposed by body forces, and second with explicit roughness described by roughness-conforming grids. Ow- ing to the minimal cost, we are able to conduct DNSs with increasing roughness Reynolds numbers while maintaining a fixed blockage ratio, as is typical in full-scale applications. The present method promises a practical, fast and accurate tool for characterising hy- draulic resistance directly from profilometry data of rough surfaces.

Original languageEnglish
Pages (from-to)418-431
Number of pages14
JournalJournal of Fluid Mechanics
Volume773
DOIs
Publication statusPublished - 01 Jan 2015

Fingerprint

Direct numerical simulation
direct numerical simulation
hydraulics
roughness
Surface roughness
Hydraulics
Reynolds number
costs
Profilometry
high Reynolds number
Costs
simulation
grids
shift

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Chung, D. ; Chan, Leon Zen Hsien ; Macdonald, M. ; Hutchins, N. ; Ooi, A. / A fast direct numerical simulation method for characterising hydraulic roughness. In: Journal of Fluid Mechanics. 2015 ; Vol. 773. pp. 418-431.
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A fast direct numerical simulation method for characterising hydraulic roughness. / Chung, D.; Chan, Leon Zen Hsien; Macdonald, M.; Hutchins, N.; Ooi, A.

In: Journal of Fluid Mechanics, Vol. 773, 01.01.2015, p. 418-431.

Research output: Contribution to journalArticle

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