Study on non-sampling field meant system of sediment discharge using hydrophone

本研究的目的是开发一种利用水听器来检测泥沙颗粒对水听器的影响的泥沙流量估算方法。根据Farmer的研究，在推移质情况下，碰撞产生的声幅与运动泥沙的动量成正比，泥沙颗粒的运动具有统计特性。因此，我们可以根据碰撞时的振幅对沉积物颗粒数量的统计来确定传递作用。结果表明：(1)振幅的统计特性强烈地依赖于泥沙的直径。(2)了解床面附近的水流速度或剪切速度是很重要的。为了获得接近底床的速度，在固结坝顶等刚性底板上安装了一个平面二维电磁测速仪。了解应用估计方法的极限也是很重要的。在此基础上，建立了包含河床形态的泥沙颗粒运动和排斥的数值模拟模型，并讨论了从声学信号(振幅)到输沙量传递矩阵的确定方法。探讨了集水区降雨泥沙径流过程的综合观测系统。

The aim of this study is to develop an estimating method of sediment discharge using a hydrophone to detect the impacts of sediment particles to the hydrophone According to farmer studies, it is known that the amplitude of the sound due to collisions would be in proportion to momentum of moving sediment In case of bed load, the movement of sediment particles has a statistical property. Therefore, we may determine a transfer role from statistics of amplitudes at collisions to numbers of sediment particles. As results, followings are pointed out.(1)Statistical property of amplitudes strongly depends on diameter of sediment.(2)It is important to know the velocity of flow near the bed or shear velocity. To get the velocity near the bed, a flat faced two dimensional electromagnetic velocity meter attached on the rigid bed such as a top of a consolidation dam. Is useful(3)It is also important to know the limit to apply the estimating method. The limit can be evaluated non-dimensional shear stress and the criteria depend on the bed gradient.According to above discussion, we developed a numerical simulation model of movement and repulsion of sediment particle including riverbed configuration, and discussed the way to determine the transfer matrix from acoustic signal (amplitude) to sediment discharge. We also discuss the integrated system to observe the runoff process of rainfall and sediment in a catchment area.