Analysis on sediment transport under wave action as particle-fluid interacting system

本文从不同角度研究了泥沙-流体相互作用的基本机理，并将其应用于片状水流泥沙运动分析。首先，测量了稠密混合流中颗粒所受的流体力，并绘制了阻力系数图。其次，观测了陡槽内颗粒流的速度分布，建立了切应力公式，分析了随机波浪作用下的紊流结构和床面切应力。应用光谱分析，取得了重大进展。并与实验结果进行了比较，验证了k-epsilon模型的可靠性。从理论上研究了流动与动床的相互作用。利用线性理论对河床侵蚀稳定性进行了描述，得出了沟槽间距受流床稳定性控制的结论。首先，进行了动床与滑移颗粒碰撞的一系列实验。仿真结果被用于仿真。其次，用拉格朗日方法模拟粒子的运动。

Aiming an application to the sediment transport analysis in sheet flow regime, basic mechanism of sediment-fluid interaction were studied from various view points.Sawamoto carried out two kind of experiments. In the first, fluid force exerting on particles were measured in dense mixture flow and a diagram of drag coefficient was proposed. In the second, velocity distributions of partic1e flow in steep chute were observed and shear stress was formulated.Tanaka analysed turbulent structure and bed shear stress under random wave action. Applying a spectral analysis, significant progress was achieved. The results were compared with experiments and k-epsilon model and reliability was checked.Izumi investigated the interaction between flow and movable beds theoretically. Formulating the stability of bed erosion by linear theory, it was shown that space of gullies is controlled by fluid-bed stability.Gotoh studied the effect of granular characteristics of sediment from two view points. At first, a series of experiments on collision between movable bed and saltationg particle were carried out. The results were utilized in the simulation. Secondly, particle movements were simulated by Lagrangian method.