近底泥沙通量的处理方法及适用性

为了正确理解悬沙运动方程底边界条件即近底泥沙通量的诸多处理方法的物理意义和适用性,避免泥沙理论分析和数值计算带来的偏差,归纳总结了近底泥沙通量的各种表达式,对它们的适用性和合理性进行分析.结果表明:以挟沙力、切应力、参考浓度或临界速度等方法处理近底泥沙通量,表达形式虽然多样,或将临界切应力换成对应的临界速度表示,或加入一些修正系数,但其物理本质不变,只是为了处理一些具体问题而做的简化或修正;挟沙力方法和切应力方法的经典形式用于描述近底泥沙通量更具一般性,这2种方法描述的物理过程有差别.

Near-bed sediment flux treatment methods and their applicability

In order to obtain a precise understanding of the physical meanings and applicability of various methods for treatment of the bottom boundary conditions of the suspended sediment motion equation,that is,the near-bed sediment flux,as well as to prevent the occurrence of the deviation between theoretical analysis and numerical calculation,the near-bed sediment flux equations are summarized and their applicability and rationality are analyzed in this paper.The results show that multiple approaches can be adopted to treat the near-bed sediment flux using the sediment carrying capacity,shear stress,and reference concentration.These approaches involve either replacing the critical shear stress with corresponding critical speed or adding some correction factors,whereas their physical nature remains unchanged,which is to deal with specific problems through correction simplification.The sediment carrying capacity and shear stress are commonly used to describe the near-bed sediment flux,and the two methods describe the physical process differently.