清水作用下全动床复式河槽泥沙输移特性及其模拟

推移质运动是河流动力学的基本问题之一,通过水槽试验探讨了清水作用下全动床复式河槽泥沙的输移特性,并通过理论分析提出了该类河道的推移质输沙率的计算方法.试验表明:在清水作用下全动床复式河槽推移质输沙率先随时间单调递增,而后随时间单调递减；推移质中值粒径先随时间大幅度增大,后随着时间的增加中值粒径增大的幅度减小,最终将趋于初始床沙中值粒径.根据推移质输沙率的变化特性,运用仙农熵的概念与理论,通过最大熵原理和变分法推导了河道粗化过程中的推移质输沙率公式,并对该公式参数的敏感性进行了分析.计算结果表明,该公式可以模拟全动床复式河槽河道粗化过程中的输沙率随时间的变化特性.

Sediment Transport Nature and Its Simulation in Fully Mobile Bed Compound Channels Under the Action of Clear Water

Sediment transport is one of the basic issues in the field of river dynamics. This paper experimentally studies the sediment transport nature in fully mobile bed compound channels under the action of clear water and then proposes the method for modeling the sediment transport rate in the type of channels. The experimental results show that the sediment transport rate first increases and then decreases with time. And the experimental results also shows that the median diameter of sediment first rapidly and then slowly increases with time, and finally approach the median diameter of the original bed material. According to the motion nature of sediment transport, the computational method for sediment transport rate in the type of channel has been proposed. In the meanwhile, the sensitivity analysis of parameters in the proposed method is undertaken. The computed results show that the method can be capable of modeling the sediment transport in the processes of clear-water action.