NUMERICAL SIMULATION OF DESTRUCTION PROCESS OF PROTECTION BLOCKS BELOW A GROUNDSILL INDUCED BY LOCAL SCOUR

Abstract

 In this paper, a numerical model was developed that introduced a protection block movement analysis using the Discrete Element Method (DEM) into an Eulerian two-dimensional flow and bed deformation model in order to predict the destruction process of the blocks below a groundsill induced by local scour. Concerning the block movement analysis by DEM, the particles were placed only the surfaces of the blocks and the riverbed to reduce the computational load. Now, hydrodynamic force acting the blocks was not considered in this model. The model applied to movable bed experiments with or without the protection blocks below a groundsill. As a result of the simulation without the blocks, the model could reproduce the local scour phenomenon in the experiment well. Moreover, in the simulation with the protection blocks, the model was found to reproduce the destruction process of the protection blocks induced by the local scour progresses although the number of blocks that flowed out was smaller than the experimental data.