AN EXPERIMENTAL STUDY ON THE DETENTION STRUCTURES ACTED BY UNSTEADY FLOW

• Main Authors: Chung, Wen-Chuan, 鐘文傳
• Other Authors: Chen, Jen-Yan
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/10431985801405989716

碩士 === 國立中興大學 === 土木工程研究所 === 83 === Due to the most developments on the slopelands, that results the reduction of the vegetation covering and the surface rounghness. Also it causes the increasing of the surface runoff and the discharge of the flow is becoming larger. The soils and sands washes away fastly. It threatens the life and fortune of the peoples living at the downstream of the slopelands. In order to delay and reduce the flow peak, this study has progressed sieres of unsteady flow hydrograph by using the computer and the cycling water flume. By means of these experiments, there can be analyzed the characteristic of various flow hydrograph, the discharge equation at flow outlet and the flood storage of the detention structures, and we can compare the peak attenuation, peak lag with different flow hydrogragh to gain the rules by designing the detention structures at the developments on the slopelands. Based on the experimental data and the theoretical analysis, the conclusion are drawn as follows: (1) The tp/tr of the real rainfalls are always left-hand types. And, the tp/tr occurence period duration of the real rainfall types effect the discharge and volume of inflow, outflow and storage. (2) The outlet width and the detention pool length effect the inflow storage, peak attenuation and peak lag. (3) The outlet experimental discharge equation is Q=1.71*b**1.03*Hd**1.49. The power of b and Hd are similar to that of theoretical value. But the discharge coefficient is smaller than that gained by theoretical value. The reason is that the sensor is placed on the above of the outlet. Not at the upstream where the flow depth is normal.