Author(s): Kazumasa Matsumoto; Xujian Wu; Michio Sanjou; Taka-Aki Okamoto; Takahiro Koshiba; Tetsuya Sumi
Linked Author(s): Michio Sanjou, Tetsuya Sumi
Keywords: Self-lining Abrasion countermeasure Strip roughness Sediment deposition PIV
Abstract: Abrasion countermeasures for sediment bypass tunnels (SBT) are necessary to improve utility and sustainability of dams. This study focuses on a countermeasure by self-lining in which strip roughness elements are attached to the tunnel wall to enhance sediment deposition and thereby to relieve damage by collision with large gravel. The purpose of this study is to reveal the flow structure and sediment deposition mechanisms over triangular strip roughness elements to investigate the feasibility of self-lining. First, flow velocity measurement by particle image velocimetry (PIV) was performed to reveal the flow structure between roughness elements. Second, sediment deposition experiment was conducted to observe the deposition processes between roughness elements and to evaluate the coverage rate of a channel wall. To clarify the optimal setups and hydraulic conditions for self-lining, nine cases with different roughness intervals and Froude numbers are considered. Results of the experiments suggest that downward flows between roughness elements cause sediment particle lift-up and prevent the sediment deposition on the channel wall.
Year: 2025