EGU25-15234, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-15234
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
 Flow Characteristics and Particle Kinematics in Bedload Transport: a CFD-DEM investigation
Xia Li, Tianxiong Zhao, and Binyu Xu
Xia Li et al.
  • Southeast University, Civil Engineering, China (xia.li@seu.edu.cn)

Bedload transport, critical in various natural and engineering systems, involves the complex interaction between particles and flowing water. Predicting bedload transport rates has long been a focal point of interest due to its significance in understanding river dynamics. Pioneering contributions from Einstein and Bagnold have led to substantial progress in this field derived from extensive laboratory and in-situ observations, which are yet to achieve the desired accuracy when validated against real-world hydrological data. The discrepancies in predictions can partly be attributed to the difficulties in accurately capturing the movements of near-bed particles and the flow field characteristics.

This paper presents a numerical investigation via Computational Fluid Dynamics-Discrete Element Method into detailed observations on particle movements and flow characteristics of bedload transport. It provides a thorough review of the assumptions and theories prevalent in current bedload models. Simulations have been conducted covering flow velocities ranging from below the generally accepted critical Shields number to the onset of bedform formation. We analyze particle trajectories and statistical behaviors under various conditions, focusing on both the motions of individual particles and the collective evolution of bedforms, and our primary results include: 1. The incipient motion of particles is a gradual process that can occur before reaching the generally accepted critical Shields number. 2. The emergence and development of bedforms under varying conditions. 3. Observations on the relationship between particle movement characteristics and the shear conditions. These findings enhance our understanding of particle-scale dynamics in bedload transport, providing a foundation for evaluating and improving existing models for predicting transport rates.

How to cite: Li, X., Zhao, T., and Xu, B.:  Flow Characteristics and Particle Kinematics in Bedload Transport: a CFD-DEM investigation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15234, https://doi.org/10.5194/egusphere-egu25-15234, 2025.