Browsing by Author "Hsieh, T. Y."

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Effect of Stony Debris Flow on Design Discharge for Tung-Pu-Ray Creek
(2004)
Hsieh, T. Y.
;
Chang, C. H.
;
Pen, S. C.
;
Yang, J. C.
;
防災與水環境研究中心
The primary objective of this research is to investigate the impact of stony debris flows of Tung-Pu-Ray Creek on its design discharge by using the quasi two-dimensional cell model for inundation simulation. The research is based on the assumption that there is a linear relationship between the actual discharge hydrograph of sediment-laden flows, and the discharge hydrograph of sediment free flows. That is, the ordinates of the discharge hydrograph of sediment-laden flows are n times of water flows. Hence, using the inundation simulation by the quasi two-dimensional cell model, one can define the extent of the impact of stony debris flows of Tung-Pu-Ray Creek on its design discharge through the calibration with the actual flood inundation of the typhoon Toraji of 1990. The simulation indicates that the actual discharge of Tung-Pu-Ray Creek's sediment flows can be determined as 1.4 times of the discharge hydrograph derived from the actual precipitation data. In other words, the weighted impact of the stony debris flows on the design discharge is approximately 0.4 times in the Tung-Pu-Ray Creek case.
Two-Dimensional Nonequilibrium Noncohesive and Cohesive Sediment Transport Model
(2009-05-01)
Hung, M. C.
;
Hsieh, T. Y.
;
Wu, C. H.
;
Yang, J. C.
;
土木工程學系
The purpose of this paper is to develop an unsteady 2D depth-averaged model for nonuniform sediment transport in alluvial channels. In this model, the orthogonal curvilinear coordinate system is adopted; the transport mechanisms of cohesive and noncohesive sediment are both embedded; the suspended load and bed load are treated separately. In addition, the processes of hydraulic sorting, armoring, and bed consolidation are also included in the model. The implicit two-step split-operator approach is used to solve the flow governing equations and the coupling approach with iterative method are used to solve the mass-conservation equation of suspended sediment, mass-conservation equation of active-layer sediment, and global mass-conservation equation for bed sediment simultaneously. Three sets of data, including suspension transport, degradation and aggradation cases for noncohesive sediment, and aggradation, degradation, and consolidation cases for cohesive sediment, have been demonstrated to show the rationality and accuracy of the model. Finally, the model is applied to evaluate the desilting efficiency for Ah Gong Diann Reservoir located in Taiwan to show its applicability.