冲积河流一维数学模型

Alluvial Mathematical Model in the Regime of Non-Equilibrium Graded Bed Load Transport

本文发展了一个模拟冲积河道河床变形的一维数学模型.此模型引入了混合层和淤积层概念模式用于模拟河床组成,并考虑了非均匀颗粒的不平衡输移,用隐式有限差分法同步求解水流泥沙连续方程式、水流运动方程和河床组成方程式.这些特点使得该模型能同步反映水流与河床相互作用和制约的关系,并能用于计算和模拟(1)河床长期变形;(2)非均匀质不平衡输沙;(3)冲淤过程河床组成变化;(4)冲刷极限状态床面覆盖作用.此外,模型还具有稳定性能好,计算步长大的特点.

A new one-dimensional alluvial mathematical model has been developed and formally tested. This model takes into account armouring effects and gran ulometric sorting by introducing the concepts of deposition layer and mixed layer, and it can also consider the spatial lag effects of bed loadtransport under unsteady flow condition. The liquid (water conservation, flow momentum conservation) and solid (sediment conservation, bed sediment composition, bed load transportation law) conservation equations are fully coupled by using the Preissmann finite-difference method. Preliminary tests show that this model can reproduce more complex physical processes involved in the engineering problems.