Taking into account granular bed resistance in turbulent bedload transport with arbitrary slope and particle shape

Abstract

<p>Turbulent bedload transport has a major influence for riverbed evolution and is still lacking a general understanding for realistic configurations with arbitrary slopes and sediments shapes. In this contribution, we explore the importance of the granular bed resistance to the fluid flow. Based on the work of Maurin et al (2018), we show that a generalized version of the repose angle of the granular material can be defined, and is able to characterize the slope influence on sediment transport rate for particle scale simulations (Maurin et al, 2015) over a large range of slopes and fluid forcing (i.e. Shields number). Extending the configuration to arbitrary particle shapes, the sediment transport rate is shown to be correlated to the variation of the granular media repose angle (Monthiller 2019), and the relevance of the latter is discussed.</p><p>Maurin, R., Chauchat, J., Chareyre B. & Frey, P. (2015). A minimal coupled fluid-discrete element model for bedload transport, Physics of Fluids, 27, 113302<br>Maurin, R., Chauchat, J., & Frey, P. (2018). Revisiting slope influence in turbulent bedload transport: Consequences for vertical flow structure and transport rate scaling. Journal of Fluid Mechanics, 839, 135-156. doi:10.1017/jfm.2017.903<br>Monthiller, R. (2019), Particle shape influence on turbulent bedload transport, Master thesis ENSEEIHT/Toulouse Univ.</p>