The Flow in Compound Cross-sectional Weir and Rating Curve

• Main Authors: Yu-Cheng Huang, 黃裕成
• Other Authors: Chan-Ji Lai
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/2gtnx2

碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 90 === 　　A compound weir is the combination of a main weir and a side weir. In low discharge, water flows in the main weir, as discharge increases water will spill over into the side weir. At this time, the wetted perimeter will rapid extend. The velocity between the main weir and the side weir is non-uniform and the flow characteristic on the weir in high or low discharges are quite different. 　　The study intends to find a possible relation between the water level and the discharge through a specially designed compound weir. The compound weir has a trapezoidal main section and a sloping side weir. Several experiments are conducted in a flume in which the compound weir is installed at the end section of the flume. A control section is formed at the weir. The discharges, the corresponding water levels and the approaching velocity profiles are measured. The results are analyzed and the discharge formulae for the compound weir as well as a dimensionless diagram of the discharge coefficient and water depth are obtained. This dimensionless discharge coefficient equation provides a guideline for designing compound weir at the same shape, but at different dimensions, for practical applications.