| Summary: | 碩士 === 國立交通大學 === 土木工程學系 === 101 === Most of the main channels of alluvial rivers are meanders. The main channel becomes the compound channel confined by the embankments during rise of flood. Assessment of channel migration and bed erosion in meandering compound channel is necessary.
The aim of this research is to investigate channel migration in meandering compound channel with inbank and overbank flows using CCHE2D model. Numerical simulations of two experimental bends show the characteristics of the secondary flow. Validations of the model, using sine-generated experimental data with bank erosion, have been performed. The model was also applied to study the morphological changes of experimental meandering compound channels and field case in Tseng-Wen Creek under changing conditions of flow and sediment.
Good agreements between the simulated and available laboratory measurements were obtained. According to simulation results, the discharge in the main channel affects the stability of the main channel. The discharge in the floodplain of compound channel increases as the water depth increases, and the effect of the centrifugal force decreases. The results also point out the importance of the flow interaction between main channel and floodplain under overbank flow condition.
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