Application of computational modeling for large wood dynamics with collisions on moveable channel beds

This study aims to analyze model reproducibility on large wood collisions on moveable channel beds. Flume experiments were conducted to observe the responses of moveable bed change with the behavior of large wood, including wood collisions. In the experiments, we employed time intervals of 5 and 9 s in wood supply, which modified the collision patterns. Subsequently, we conducted simulations based on the experimental conditions. Herein, to analyze the wood collision effect in the simulations, we employed the dashpot-spring model in a large wood dynamics model. Subsequently, we compared the simulations with and without wood collision and discussed the reproducibility of the model. The results of the simulations and experiments revealed that the wood pieces exhibited diverse behaviors, including floating, sliding, deposition, plane rotation, rolling, collision, remobilization, jam formation, and causing local bed changes. In particular, the results indicate that model reproducibility is dependent on wood collision because this can actively alter wood deposition patterns. We also described the piping and tunnel erosion processes linked to wood collision and moveable beds and suggested the corresponding, suitable computational treatment. This study presents an experimental and modeling methodology on wood collision and the interaction between bed change and large wood. Thus, useful information for solving numerical difficulties linked to large wood dynamics, including wood collisions, is provided.