平面二维全沙数值模拟方法及其应用

Application of finite volume method in plane 2-D numerical model for nonuniform sediment

采用有限体积法对正交曲线坐标系下的平面二维水沙微分方程进行了离散,建立了平面二维全沙数学模型.在一概化的单边突然扩宽河道中对河床冲淤过程中悬移质含沙量及其级配、推移质输沙率及其级配、床沙级配等沿时空变化特性进行了计算分析,并模拟出了由河床冲刷引起的床沙粗化、抗冲层的形成过程以及河床淤积过程等泥沙特性的变化.数值计算结果表明,该模型在定性上能正确地模拟水流以及河床的冲刷、淤积过程.

A plane 2-D mathematical model for unsteady flow and nonuniform sediment based on body-fitted curvilinear coordinate system is established. The finite-volume method is adopted for resolving the flow equation together with nonequilibrium transportation equations of suspended load and bedload. The suspension concentration and its particle distribution, the transport rate of the bedload and its particle distribution, and the particle distribution of riverbed are calculated during riverbed erosion and deposition of riverbed in a simplified suddenly widened riverway. The coarsening process of riverbed and the process of forming a layer to resist erosion are simulated. The result shows that the flow field and the process of riverbed erosion and deposition can be simulated qualitatively by this method.