EGU21-4364, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-4364
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Analytical approach unifying the two-regime scaling for bedload particle motions

Zi Wu1, Arvind Singh2, Efi Foufoula-Georgiou3, Michele Guala4, Xudong Fu1, and Guangqian Wang1
Zi Wu et al.
  • 1Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China
  • 2Department of Civil, Environmental and Construction Engineering, University of Central Florida, Orlando, FL 32816, USA
  • 3Department of Civil and Environmental Engineering, University of California Irvine, Irvine, California 92697, USA
  • 4St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota 55414, USA

Bedload particle hops are defined as successive motions of a particle from start to stop, characterizing one of the most fundamental processes describing bedload sediment transport in rivers. Although two transport regimes have been recently identified for short- and long-hops, respectively (Wu et al., Water Resour Res, 2020), there still lacks a theory explaining how the mean hop distance-travel time scaling may extend to cover the phenomenology of bedload particle motions. Here we propose a velocity-variation based formulation, and for the first time, we obtain analytical solution for the mean hop distance-travel time relation valid for the entire range of travel times, which agrees well with the measured data (Wu et al., J Fluid Mech, 2021). Regarding travel times, we identify three distinct regimes in terms of different scaling exponents: respectively as ~1.5 for an initial regime and ~5/3 for a transition regime, which define the short-hops; and 1 for the so-called Taylor dispersion regime defining long-hops. The corresponding probability density function of the hop distance is also analytically obtained and experimentally verified. 

How to cite: Wu, Z., Singh, A., Foufoula-Georgiou, E., Guala, M., Fu, X., and Wang, G.: Analytical approach unifying the two-regime scaling for bedload particle motions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4364, https://doi.org/10.5194/egusphere-egu21-4364, 2021.

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