This paper proposes a hydrodynamic/sediment model for simulating bedload sediment through a river section. Firstly, flow characteristics such as depth-averaged velocity were obtained by solving the governing equation, which is derived from the Reynolds equations and allows for taking into account the gravity, bed shear stress, turbulent diffusion force and secondary flow in calculations. | BÀI BÁO KHOA HỌC A HYDRODYNAMIC/SEDIMENT MODEL FOR SIMULATING BEDLOAD SEDIMENT IN THE RIVER Chien Pham Van1 Abstract: This paper proposes a hydrodynamic/sediment model for simulating bedload sediment through a river section. Firstly, flow characteristics such as depth-averaged velocity were obtained by solving the governing equation, which is derived from the Reynolds equations and allows for taking into account the gravity, bed shear stress, turbulent diffusion force and secondary flow in calculations. Four criteria (. root mean square error, mean absolute error, Nash-Sutcliffe efficiency, and correlation coefficient) were used to access the quality of computed results, revealing that a good agreement between simulations and observations was obtained at the studied river section. Secondly, nine relations for determining bedload sediment transport rate and bedload sediment discharge were considered and compared to identify suitable ones. The results showed that the relation proposed by Camenen and Larson (2005) proved to be well adopted, providing even better results than the others. Finally, future modeling efforts and wide-ranging applications of the model were discussed. Keywords: bedload sediment, sediment rate, hydrodynamic/sediment model, Danuble river. 1. INTRODUCTION1 Sediments are inherent components of riverine waters, which are transported under the form of suspended and bedload sediments. Suspended sediment normally consists of finegrained materials and relates to water quality, pollution, and aquatic ecology. On the contrary, bedload sediment consists of coarser-grained materials that can be sliding, rolling, and saltating over short distances in region close to the riverbed. The bedload sediment often occurs during episodic evens such as floods. Bedload sediment usually involves bed evolution or morphological changes, and thus the navigation and flood mitigation infrastructure. Therefore, bedload sediment needs to be quantitatively accessed in .
