Application of Unified Coordinate System to Dam-Break Shear Flows over Erodible Bed

• Main Authors: Ya-TingHuang, 黃亞婷
• Other Authors: Yih-Chin Tai
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/14303711690168446003

碩士 === 國立成功大學 === 水利及海洋工程學系 === 102 === When the dam-break flow occurs at the loose bed, due to the erosion, the sediment of the erodible bed will be taken away. Since the decreasing flow velocity and the influence of the topography, the sediment will be deposited on the bed. Either in erosion or by deposition, the basal surface evolves due to the sediment exchange through the interface between the flowing layer and the stagnant bed. In the present study, we combine a sharp-capturing, Riemann-solver-free non- oscillation central (NOC) scheme with Unified Coordinate method to describe the development of dam-break shear flow on deforming basal surface, and to discuss the influence of sediment concentration distribution of the bed and the flowing layer on erosion and the deposition. Consider a three-layer structure along the flow thickness, where a pure-water layer lies above a mixture layer of water and grains, and they flows over a water-saturated granular substratum. We postulate that the mixture transport layer is sheared and exhibits a discontinuity of sediment concentration at the interface between the mixture layer and the substratum. The numerical results show that our postulation is more consistent with the analysis of experiment.