Basic study of Design Method for the Main Channel of Meandering Compound Channels

曲流复合河道主河道设计方法基础研究

基本信息

批准号：
10450183
负责人：
FUKUOKA Shoji
金额：
$ 8.32万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450183/
关键词：
Compound meandering channel Clnsteadiness of Flood flow Storage volume in a river Planform Numerical analysis Accuracy of discharge measurement 水理実験複断面河道蛇行洪水ハイドログラフ水位-流量関係相対水深河道設計

项目摘要

(1) Comparing stage hydrographs for meandering compound channel and meandering single channel it was observed that, compound meandering channel had early response giving high values during rising stage and delayed response giving high values during falling stage. Also for both compound meandering channel and meandering single channel, increase of sinuosity and unsteadiness brings faster occurrence of the maximum velocity and the large increase rate of the depth in the rising stage.(2) A quantitative estimation of the flood flow storage and attenuation of the peak discharge in channels was investigated. Laboratory experiments in a compound meandering channel were performed and observed flood data from Otagawa river were analyzed. Results of comparison of the experimental data and Otagawa river data indicated similar characteristics of flood flow storage.(3) A comparison between experimental results and a 2 -dimensional unsteady flow numerical model simulations is made for flood propagation in a compound meandering channel. The model is based on a finite volume discretization on a staggered gird with upwind scheme in flux is presented, it handles drying and wetting process for a flood plain, complex geometry and discontinuities, which are the main requirements for modeling compound channel flows. The existing knowledge on flood flow phenomenon in compound channels is advanced through comparative studies of unsteady flow experiments and numerical simulations. Comparison between measured date and model simulations show generally good agreement.(4) Since most of the rivers in Japan are compound meandering channels, which have complex flow field, we check the accuracy of discharge measurements of those compound channels. The accuracy of discharge measurements is investigated in a compound meandering channel by using a there dimensional numerical analysis. The discharge measurement is clarified from the Eulerian and the Lagrangian methods.

(1)比较曲流复合河道与曲流单河道的阶段过程线，发现复合曲流河道在上升阶段响应较早，出现高值；在下降阶段，响应延迟出现高值。同样，无论是复合曲流河道还是曲流单河道，曲流和非定常性的增加都会带来上升阶段最大流速出现较快、水深增幅较大的情况。(2)洪水蓄积量和衰减量的定量估算。研究了通道中的峰值放电。在复合曲流河道中进行了实验室实验，并对太田川河的洪水观测数据进行了分析。实验数据与太田川河数据的对比结果显示了相似的洪水蓄洪特征。(3)针对复合曲流河道洪水传播的情况，将实验结果与二维非定常流数值模型模拟进行了比较。该模型基于交错网格上的有限体积离散化和逆风流方案，它处理洪泛区的干燥和湿润过程、复杂的几何形状和不连续性，这是模拟复合河道流的主要要求。通过非定常流实验和数值模拟的比较研究，加深了对复合河道洪水流现象的现有认识。实测数据与模型模拟结果的比较显示总体吻合较好。(4)由于日本河流大多为复合曲流河道,流场复杂,因此对复合河道流量测量的精度进行检验。通过使用多维数值分析，研究了复合曲流通道中流量测量的准确性。放电测量由欧拉法和拉格朗日法阐明。