Extensive fine sediment infiltration into void spaces in coarse bed material can potentially alter river morphodynamics and aquatic ecosystems. Understanding and modelling the mechanisms of fine sediment movement and accumulation in gravel bed is therefore of high significance. In this paper, we applied the Discrete Element Method (DEM) for gravel bed flume with different sizes of fine sediment. In the model, we assumed a non-slip condition at the sediment-water interface and solely considered gravitational settling. Furthermore, the sediment particle properties and interaction laws are inputted into DEM and lead to the collective behavior of the dissipative many-particle system. From the results of particle simulation, we can extract information of the gravel bed packing, grain size distribution, and porosity variation. The calculated results agree well with the measurements conducted by other authors. A further development of the model will be applied to quantify the sediment exchange rates between different bed layers in a new hydro-morphodynamic model for graded sediments in rivers considering the bed-porosity change.     «

Extensive fine sediment infiltration into void spaces in coarse bed material can potentially alter river morphodynamics and aquatic ecosystems. Understanding and modelling the mechanisms of fine sediment movement and accumulation in gravel bed is therefore of high significance. In this paper, we applied the Discrete Element Method (DEM) for gravel bed flume with different sizes of fine sediment. In the model, we assumed a non-slip condition at the sediment-water interface and solely conside...     »