Conference Proceedings

Direct numerical simulation of turbulent flow over spanwise-varying roughness

MX Xie, A Rouhi, D Chung, N Hutchins

Proceedings of the 21st Australasian Fluid Mechanics Conference, AFMC 2018 | Published : 2018

Abstract

© 2018 Australasian Fluid Mechanics Society. All rights reserved. We report direct numerical simulations (DNS) of turbulent flow through an open channel over spanwise-alternating patches of smooth and rough surfaces. The width of the patches is varied from s/h ≈ 0.40 to s/h ≈ 12.72, where h is the height of the channel. The roughness elements are fully resolved; here, they are three-dimensional sinusoids with fixed height k/h = 0.056 and fixed wavelength λ = 7.1k. The friction Reynolds number based on the global wall shear stress is 590. As the patch width increases, we find that the skin-friction coefficient decreases and the contrast between the rough and smooth wall shear stresses decreas..

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