Study on hydro-environmental properties of rubble weir constructed of coarse rokcs

粗石砌筑的碎石堰水环境特性研究

基本信息

批准号：
12650513
负责人：
MICHIOKU Kohji
金额：
$ 2.3万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650513/
关键词：
Rubble mound weir Porous structure subsurface flow flow resistance discharge curve Image processing Particle tracking velocimetry Rapidly varied flow 堰越流捨石安定性再曝気開水路流水面変動

项目摘要

A "rubble mound weir" was proposed as a river discharge control system. The weir is expected to be a nature-friendly structure for controlling flow discharge in a way that it allows streamwise movement of aquatic animals. In order to make a suitable design of the structure, its hydrodynamics and hydro environmental properties were examined by performing laboratory experiments and a theoretical analysis. First, a laboratory experiment was carried out in order to find functional dependency of discharge on parameters such as water depth, weir's porosity, rubbles size, etc.. The weir model constructed of pebbles was installed in an open channel, where weir's dimension and grain diameter were varied. A one-dimensional flow analysis was performed to obtain a solution for water surface profile inside the weir. Flow resistance in the weir was evaluated from an experimental formula for turbulent porous media flow. The solution leads to a functional relationship between discharge and upstream wa … More ter depth. A theoretical discharge-curve was obtained through the analysis as functions of Reynolds number, porosity, specific grain size, weir's aspect ratio, dimensionless water depth, etc.. The solution was well correlated with the experimental data under wide range of flow conditions. Second, local flow structure around the weir was experimentally examined by applying a particle image velocimetry, PIV, which provides information of time and space scales of the flow fields. Because habitats of aquatic lives are very much influenced by time-dependent flow structure, it is very important from an environmental point of view to take time- and space- scales of flow motions into consideration in determining the weir's dimension. Third, a multi-variables analysis was applied to pick up various scales of energy-contain eddies ; some of them are responsible in collapsing the weir, some play important roles in gas transfer between the air-water interface, the others affects activities of aquatic animals, and so on. Fourth, dynamic stability of the structure was investigated by measuring pressure fluctuation inside the weir's porous body. The critical condition for failure or collapse of the structure was given from local flow force that takes the maximum value at the downstream side of the weir top surface. Integrating results from the present research project, one can make structural design of the rubble mound weir from both of hydrodynamic and hydro-environmental points of view. The rubble mound weir is expected to be a river structure that better preserves ecological system than conventional metal or concrete weirs. Less

“瓦砾”堰被曝光是一种对自然友好的结构，用于控制流动动物的电影运动，以便对结构进行合适的设计，iDrody and indroverymants和hydro环境特性。通过执行实验室实验和TEORETICE ANARAGESS进行检查。，进行堰的尺寸和晶粒直径。雷诺数，特定的晶粒，堰的纵横比，无量纲的水深度等。解决方案与孔孔的范围内的实验数据相关。图像图像图像IMEMEMETRY，PIV，提供流场的时间和空间尺度的信息，从环境的角度到流动时间的空间尺度来确定堰的尺寸 - 用于拾起各种能量范围的范围，造成堰的量表；通过测量堰的多孔体内的压力波动来研究结构的动态稳定性从水力动力学和水力环境的角度来看，瓦砾式堰式堰的视角都将是一种比传统的金属或混凝土更少的河流结构。