DEVELOPMENT OF TWO-DIMENSIONAL NUMERICAL MODEL FOR VARIATION OF BED AND CHANNEL IN GRAVEL AND STONY RIVER

建立了砂石输运数值模型和洪水准三维数值模型。砂砾输运模型将床质、表层和地下的粒度分布与砂砾输运函数联系起来。准三维模型使用垂直平均方程和力矩方程作为控制方程，允许将预先假设的水平速度线性分布和二次垂直速度和压力分布结合起来。这些模型也是基于有限体积法和近似黎曼解算器。通过对实验数据的验证，这些模型能够再现河床的退化、加香和下游细化过程，以及弯曲河道和河流汇合处水流的复杂行为。

Numerical model for gravel transport and quasi-3D numerical model for flood flows were developed. The model for gravel transport links grain size distributions in the bed load, surface layer and subsurface with the gravel transfer function. The quasi-3D model uses the vertically averaged and moment equations as governing equations to allow for the incorporation of pre-assumed linear distribution of horizontal velocity and quadratic vertical velocity and pressure distributions. These models are also based on finite volume method with approximate Riemann solver. Through the verification against experimental data, these models have ability to reproduce the process of bed degradation and aggradation with aromouring and downstream fining as well as the complex behavior of the flows in curved channel and in river confluence.