Simulation and Application of Sediment Exchange Mechanism
|Keywords:||交換機制;Sediment Exchange Mechanism|
Sediment transport mechanism in rivers is quite complicated. This study is under the framework of the 1-D finite analytic mobile-bed model, and refers Hsu’s (2002) results. In the model, the sediment transport rate is divided into suspended load and bed load. The bed load and the equilibrium vertical concentration profile of the suspended load are calculated by van Rijn’s (1984) formulas. In addition, the actual concentration of suspended load is concerned. The difference between the two concentration profiles determines the exchange rate between the suspended load and the bed load, and also the quantity of channel scour or deposition. Suryanarayana’s (1969) experimental data for the scour and deposition cases of uniform and non-uniform bed material are adopted for the calibration of the proposed model. Results show that consideration of abovementioned exchange mechanism can accurately simulate the experimental data. Finally, to demonstrate the practicability of the model, the impact of the flushing from Ah-Kong-Diann Reservoir on its downstream channel is simulated. The shortterm and longterm impacts on downstream scour and deposition of Ah-Kong-Diann Creek due to various sediment concentrations released from the Reservoir are evaluated. The results provide some useful information for the reservoir flushing operation in future.
|Appears in Collections:||Thesis|