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LARGE-EDDY AND DIRECT SIMULATIONS OF SINK FLOWS OVER ROUGH WALLS

Junlin Yuan
Department of Mechanical and Materials Engineering Queen's University Kingston, ON, K7L 3N6, Canada

Ugo Piomelli
Dept. of Mechanical Engineering University of Maryland College Park, MD 20742, USA; Department of Mechanical and Materials Engineering Queen's University, Kingston (ON) K7L 3N6, Canada

Résumé

Turbulent sink-flow boundary layers over smooth and rough walls are studied using large-eddy and direct numerical simulations. Various acceleration levels are applied, yielding a wide range of Reynolds number (Reθ = 372 − 2748). The effects of acceleration and roughness on the flow are investigated. The results highlight that acceleration and roughness have opposite effects, consistent with previous investigations. Acceleration is found more important than roughness on outer-region turbulence. In the near wall, roughness causes spatial variations of the mean velocity that are correlated with the geometry. The streaky structure of the near-wall layer is significantly modified.