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

提出了一个“瓦砾丘很奇怪”作为河流排放控制系统。奇怪的预计将是一种自然友好的结构，用于控制流量排放，以使水生动物流动。为了对结构进行合适的设计，通过执行实验室实验和理论分析来检查其流体动力学和水力环境特性。首先，进行了实验室实验，以找到排放对参数的功能依赖性，例如水深，奇异的孔隙率，垃圾尺寸等。在开放的通道中安装了由鹅卵石构成的奇怪模型，其中奇怪的尺寸和谷物直径变化了。进行了一维流量分析，以获取奇怪内部水表面剖面的解决方案。从湍流多孔介质流量的实验公式中评估了奇异的流动性。该解决方案导致排放和上游WA之间的功能关系……更深入。通过分析获得了理论排放曲线，作为雷诺数，孔隙率，特定晶粒尺寸，奇异的纵横比，无量纲的水深度等的功能。该溶液与在广泛流量条件下的实验数据良好相关。其次，通过应用粒子图像速度计，PIV来对奇怪的局部流量结构进行了检查，因为水生生物的栖息地受到时间依赖性流量结构的很大影响，从环境的角度来看，在确定奇怪的尺寸方面，考虑到时间和空间尺度，这一点非常重要。第三，应用多变量分析来拾取各种含能量的涡流。其中一些是造成奇怪的，有些在空气水界面之间的气体转移中起重要作用的原因，另一些则影响水生动物的活动，等等。第四，通过测量奇怪体内的压力波动来研究结构的动态稳定性。结构故障或崩溃的临界条件是从局部流动力中给出的，该局部流动的最大值在奇怪的顶部表面的下游侧。整合本研究项目的结果，可以从流体动力和水力环境的角度来对瓦砾丘的结构设计。预计瓦砾丘很像是一种比传统的金属或混凝土陌生人更好地保存生态系统的河流结构。较少的