Hydraulic characteristics in vegetated open channel flows.

植被明渠水流的水力特性。

基本信息

批准号：
05660279
负责人：
KATO Osamu
金额：
$ 1.34万
依托单位：
SAGA University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The objectives of this study are to investigate the effects of the sway of flexible standing roughness elements on the profiles of mean velocity, turbulence intensities and Reynolds stress, and to develop a theoretical model which can explain the experimental results.A relationship between the deflection of reeds and water velocity was investigated in order to understand the physical characteristice of reeds, e.g.flexural rigidity.The reeds as the roughness elements were used Hydrilla verticillata(L.f).Casp.KUROMO and Potamogeton oxyphyllus Miquel, YANAGIMO.The experiments were conducted in a recirculating open channel 7.0m long, 0.4m wide, and 0.4m deep. The roughness elements were placed in a bed 0.9m long with the same distance in a between in a square lattice. For each roughness, the experiment was divided to three cases.In this model, the momentum equations are derived for the steady uniform flow and the displacement of roughness elements is analyzed as the static deflection problem of cantilever, in which the hydrodynamic force is converted into the external force acting on the roughness elements. The flow field may be conveniently separated into two region ; (1)the outer region, which corresponds to the region above roughness elements, (2)the inner region, which corresponds to the region within roughness elements.The analytical velocity profile show that the theory could bu used efficiently to predict the characteristics of flow.The hydrodynamic force acting on one roughness element is assumed to be proportional to the projected area in the flow-direction and to the square of mean velocity, and the displacement of roughness elements is derived from the bending moment at an arbitrary position.The calculated deflection of the roughness element agree to all of the experimental profiles with exception of the case of slow velocities.

这项研究的目的是研究柔性站立粗糙度要素的影响对平均速度，湍流强度和雷诺的压力的影响，并开发出一个理论模型，可以解释实验结果。在理解的是，在理解的是，在理解的是芦苇和水速度的偏差之间，因为理解了Remity e.g。使用的Hydrilla verticillata（L.F）.casp.kuromo和Potamogeton oxyphyllus miquel，Yanagimo。实验是在循环的7.0m长，0.4m宽的开放通道中进行的，宽0.4m，深0.4m。粗糙度元素被放在0.9m长的床中，在正方形的晶格中，在两者之间的距离相同。对于每种粗糙度，将实验分为三种情况。在此模型中，将动量方程得出稳定均匀的流动，并将粗糙度元件的位移分析为悬臂的静态偏转问题，其中流体动力力被转化为外部力在粗糙度元素上作用的外部力量。流场可以方便地分为两个区域。 (1)the outer region, which corresponds to the region above roughness elements, (2)the inner region, which corresponds to the region within roughness elements.The analytical velocity profile show that the theory could bu used efficiently to predict the characteristics of flow.The hydrodynamic force acting on one roughness element is assumed to be proportional to the projected area in the flow-direction and to the square of mean velocity, and the displacement of roughness elements is源自任意位置的弯矩。粗糙度元件的计算偏转同意所有实验曲线，但速度慢除了情况。