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You are here : eLibrary : IAHR World Congress Proceedings : 32nd Congress - Venice (2007) : THEME A: Engineering and Management of Fresh-water Systems : Numerical study on the bed evolution process of channels with complex geometries
Numerical study on the bed evolution process of channels with complex geometries
Author : Hao Zhang, Hajime Nakagawa, Yasunori Muto and Yoshio Muramoto
A two-dimensional numerical model is developed to investigate the morphodynamics of channels with complex geometries. The model is formulated on a collocated unstructured mesh with the finite volume method and consists of a hydrodynamic module, a sediment transport module and a bed deformation module. In the hydrodynamic part, the depthaveraged unsteady shallow water equations are solved, together with methods to account for the effects of secondary flows on both the mean and the near-bed velocities. The sediment transport so far is assumed to take place in the form of bedload only. The bedload transport rate is evaluated with a deterministic semi-empirical formula. The local bed slope has great influence on the sediment transport rate and direction, especially in the neighbourhood of river hydraulic structures. This has been paid much attention in the sediment transport module. The final part, the bed deformation module, is based on the sediment continuity equation. The flow field, sediment transport and bed deformation in the model are coupled and solved in a quasi-steady way. When one of them is under calculation, the others are considered as unchanged. The numerical model has been applied to predict the channel evolution process due to natural and human-induced causes and factors in a large-scale physical model experiment. It is found that the simulation result is quite encouraging.
File Size : 2,028,034 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 32nd Congress - Venice (2007)
Article : THEME A: Engineering and Management of Fresh-water Systems
Date Published : 01/07/2007
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