Effect of small roughness elements on thermal statistics of a turbulent boundary layer at moderate Reynolds number

Ali Doosttalab, Guillermo Araya, Jensen Newman, Ronald Adrian, Kenneth Jansen, Luciano Castillo

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

A zero-pressure-gradient turbulent boundary layer flowing over a transitionally rough surface (24-grit sandpaper) with k+∼11 and a momentum-thickness Reynolds number of approximately 2400 is studied using direct numerical simulation (DNS). Heat transfer between the isothermal rough surface and the turbulent flow with molecular Prandtl number Pr=0.71 is simulated. The dynamic multiscale approach developed by Araya et al. (J. Fluid Mech., vol. 670, 2011, pp. 581-605) is employed to prescribe realistic time-dependent thermal inflow boundary conditions. In general, the rough surface reduces mean and fluctuating temperature profiles with respect to the smooth surface flow when normalized by Wang & Castillo (J. Turbul., vol. 4, 2003, 006) inner/outer scaling. It is shown that the Reynolds analogy does not hold for y+

Original languageEnglish (US)
Pages (from-to)84-115
Number of pages32
JournalJournal of Fluid Mechanics
Volume787
DOIs
StatePublished - Dec 8 2015

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Keywords

  • turbulent boundary layers
  • turbulent flows

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

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