Document Type
Article
Publication Date
2-2021
Abstract
We present results from open-channel, Euler–Lagrange (EL) simulations of turbulent flow over an erodible particle bed at a shear Reynolds number of Reτ=180 . Upon space and time averaging, our simulations correctly reproduce the Wong & Parker (ASCE J. Hydraul. Engng, vol. 132, issue 11, 2006, pp. 1159–1168) bedload transport relation (WP). However, local and instantaneous sediment flux shows orders of magnitude scatter around the WP prediction. Visualization of the vortical structures using swirling strength shows the existence of bed-penetrating Kelvin–Helmholtz (KH) vortex packets, which coupled with particle inertia are primarily responsible for the large scatter. The results also show that Euler–Euler (EE) simulations, where the individual sediment grains are not distinguished, are still able to reliably capture the turbulent shear stress variation, however, they do not capture the wide distribution of sediment flux indicative of saltating transport. The KH vortices induce non-zero streamwise and bed-normal velocities at the upper surface of the bed, which must be considered in EE simulations.
Recommended Citation
Guan, L., Salinas, J., Zgheib, N., & Balachandar, S. (2021). The role of bed-penetrating Kelvin–Helmholtz vortices on local and instantaneous bedload sediment transport. Journal of Fluid Mechanics, 911, A50. doi:10.1017/jfm.2020.1060
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Publication Title
Journal of Fluid Mechanics
DOI
10.1017/jfm.2020.1060
Comments
© The Author(s), 2021. Published by Cambridge University Press