Author(s): Takayoshi Higuchi; Takahiro Saitoh; Yoshihiko Shimizu
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Keywords: Local scour; Weir; Groundsill; E-MPS; DEM
Abstract: Riverbed degradation occurs in many rivers of Japan. It damages river crossing structures, such as weirs and groundsills, with backward facing steps. If a large flood occurs in such a situation, it is feared that the blocks protecting the riverbed will be washed away due to local scour downstream from the structures. We conducted a vertical two-dimensional numerical simulation of local scour occurring downstream from river crossing structures. Local scour is a complex phenomenon due to the interaction between flow and sediment; therefore, advanced numerical simulations are necessary for expressing such dynamic behavior. A coupling method of the Explicit Moving Particle Simulation (E-MPS) method and the Discrete Element Method (DEM) has been developed to overcome the difficulty. The E-MPS method is a particle method that the implicit computational scheme of the conventional MPS method for the pressure Poisson equation is solved by explicitly. To investi- gate the applicability of the present coupling method to local scour occurring downstream from river crossing structures, we compared the numerical results from the present method simulation with those from the mova- ble-bed hydraulic model experiment we conducted.
Year: 2020