3D–3D Computations on Submerged-Driftwood Motions in Water Flows with Large Wood Density around Driftwood Capture Facility

The accumulation of driftwood during heavy rainfall may block river channels and damage structures. It is necessary to mitigate such effects by periodically capturing removing from rivers. In this study, the behavior in open-channel flows with a relatively large wood density was modeled numerically. water flow motion were solved three-dimensionally, an Euler-type model coupled Lagrange-type model. A piece as set connected spherical elements straight line for easy analysis using discrete element method. Wood specific gravity exceeding 1 will travel along position near riverbed be affected bed friction. addition, friction forces sliding rolling motions are considerably different. Therefore, numerical model, term introduced between considering anisotropy force. variation drag force on also considered depending angle trunkwise direction direction. applied under same conditions those used laboratory experiment around inlet-type capture facility. computational results showed that proposed could qualitatively reproduce secondary patterns at approaching reach ratio found strongly turbulence Manning roughness coefficient.