Study on Generalized theory for Sediment Transport Process in Unsteady Flow

随机模型较好地描述了非定常和非均匀流中泥沙输移的时空非平衡过程。该模型由三个子系统组成；1)泥沙从河床上的移出，以泥沙的吸收速率为特征；2)以步长为特征的输移的空间侧；3)以运动周期为特征的输移的时间侧。水力实验表明了该模型的适用性和现象的细节。三个子系统根据自身的动力学特性和概率特性与水力参数相关联，并用相应的方程近似地表达了各自的关系。设计的实验表明了它们的适用性。对非定常明渠流动的湍流结构进行了实验研究。为了系统地根据非定常的变化来考察水流的变化，定义了非定常参数，该参数是由基流的性质和水深的时间变化组成的。利用所提出的参数，系统地描述了一维水力量和流动结构的时间变化。

The stochastic model quite well describes the temporal and spatial non-equilibrium processes of the sediment transport in both the unsteady and non-uniform flow. This model is consisted of the three subsystems; 1) dislodgement of the particle from the bed characterized by the sediment pick-up rate, 2) the spatial side of the transport characterized by the step length, 3) the temporal side of the transport characterized by the moving period. The hydraulic experiments shows the applicability of the proposed model and the details of the phenomena.The three subsystems are related to the hydraulic parameters based upon both the dynamics and the probabilistic properties of themselves, and the respective relations are approximately expressed by the appropriate equations. Their applicabilities are shown by the devised experiments.The turbulent structure of the unsteady open channel flow is experimentally investigated. In order to examine the change of the flow according to that of the unsteadiness systematically, the unsteady parameter is defined which is constituent of both the properties of base flow and the temporal change of the water depth. By using the proposed parameter, the 1-dimensional hydraulic quantities and temporal change of the flow structure are systematically described.