2024 Volume 80 Issue 17 Article ID: 24-17064
Effect of the channel width on the movement mechanism of tsunami boulders was analyzed by using a three-dimensional numerical simulations of coupled fluid-solid motions, and simulating movement of tsunami boulders caused by dam-break flows. A cubic tsunami boulder model with a size of approximately 0.1 m was used to analyze multiple cases with channels of different widths ranging from 0.4 m to 2.4 m. The results showed that the narrower the channel, the longer the tsunami boulder traveled. However, the fluid forces in the downstream direction decreased as the channel narrowed. This is because the buoyancy force acting on the boulder increases as the water level rises, and as the channel narrows, resulting in smaller vertical contact forces acting on the bottom of the boulder and streamwise contact forces against fluid forces. Moreover, it was demonstrated that the drag coefficient generally increased as the channel narrowed.
