Large eddy simulation of sediment transport in high flow intensity by discrete particle method

Abstract

The processes of sediment transport in high flow intensity are studied through numerical simulation using a coupled CFD (computational fluid dynamics)-DPM (discrete particle method) model with a focus on discussing the co-existence problem of bed load and suspended load and the corresponding sediment concentration distribution. It is shown that for the sediment-laden flows, the components of turbulence intensity decrease slightly as sediment concentration increases. The bed load and suspended load both coexist in a transition layer. Particle collision plays an important effect on the velocity of bed load movement. The total sediment transport rate obviously increases with the increase of flow intensity, but the bed load transport rate does not clearly increase. In the present study, the maximum value of suspended sediment concentration curve is about 7%, and increases with the increase of the flow intensity. The simulation results are generally consistent with experimental observation.

Keywords:

• Bed load
• sediment concentration distribution
• sediment transport rate
• suspended load
• turbulence intensity

Acknowledgements

The authors are grateful to professor Ji Chunning, Tianjin University for his constructive comments, which helped to significantly improve the quality of the manuscript. The authors also thank the three reviewers for insightful suggestions. Some numerical simulations were performed on the Explore 100 cluster system of Tsinghua National Laboratory for Information Science and Technology.

Additional information

Funding

This work was financed by the Natural Science Foundation of China (Grant No. 51639005; 51779170) and the National Key R&D Program of China (Grant No. 2017YFC0405202).