Hydraulic Characteristics of Detention Pond with Inverted V-notch Outlet

• Main Authors: Jia-Shiang Kang, 康嘉翔
• Other Authors: 陳正炎
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/56591388995684573522

碩士 === 國立中興大學 === 土木工程學系所 === 95 === The study focused on the investigation of inverted V-notch weirs. Four types of inverted V-notch weir outlets were employed in the experiments. Based on the hydrology continuity equation together with a Runge-Kutta numerical model, the characteristics of flood detention can be calculated. The validity of the proposed numerical model was also verified by the measurement data from the experiments conducted in this research. The results of the study are summarized as follows: 1.By using the Runge-Kutta numerical model based on the governing equations from (3-17) to (3-19) of triangular and trapezoidal inflow hydrographs, the outflows were well predicted compared with the data of measurements conducted in this research. 2.As the peak inflow reduction (κ) becomes larger when the characteristic parameter of the triangular or trapezoidal inflow hydrograph is small. On the other hand, a decrease of the bottom width (b) of the inverted V-notch weir outlet leads to an increase e of the κ value. Moreover, with the same characteristic parameter of the triangular inflow hydrograph, a larger κ value results in a greater dimensionless peak lag time (Ts) is larger while the value of κ becomes larger. However, the κ value of κ becomes smaller when the inflow hydrograph is trapezoidal. 3.With the same amount of the peak outflow, as the characteristic parameter of the triangular inflow hydrograph (β) increases, the dimensionless storage volume (Sf*) of the detention pond decreases. In contrast, when the characteristic parameter of the trapezoidal inflow hydrograph (γ) increases, the value of Sf* becomes larger. 4.In terms of the storage volume, an inverted V-notch weir outlet generally needs less space than that of a rectangular spillway. Compared to the Sutro weir, on the other hand, with trapezoidal inflow hydrographs an inverted V-notch weir outlet need less space than a rectangular spillway when the value of κ is smaller than 0.1.