THREE-DIMENSIONAL SIMULATION OF TURBIDITY CURRENT AND BED DEFORMATION AROUND SEDIMENT RELEASE FACILITY AT DAM

Abstract

 This study investigated sediment release from bottom outlet at dam by 3D numerical simulation of turbidity current and bed deformation. The numerical model was developed by customizing the open-source CFD library OpenFOAM. The erosion of cohesive sediment was modeled using the past experimental result. The numerical model was validated in the field measurement of sediment release. The field data taken after sediment release operation showed the existence of scour hole expanding laterally in front of the inlet of the sediment release conduit. The numerical simulation reproduced the scour hole with sufficient accuracy. The concentration of turbidity (i.e., SS) was also well simulated quantitatively. Contribution of the scour process to SS was evaluated using the result of the simulation. The numerical simulation revealed the phenomenon that, in some time interval, sediment is temporarily efficiently eroded during sediment release. The numerical model and findings of this study will be useful to optimize operation of sediment release gate to mitigate reservoir sedimentation of cohesive sediment.