複合堰是水利工程上常見的工程設施，用於控制或調整河道流量。本研究利用Flow-3D商用軟體模擬水流流經四種複合銳緣堰之流場，分析水位及流量關係，將模擬所得之水位流量關係與實驗資料及相關理論公式進行比較。由數值模擬結果之水位流量略小於實驗值，水位與流量為實驗值之93~95%，顯示Flow-3D對於複合銳緣堰流場模擬具有良好效益。
分析四種複合堰型過堰剖面之流速分布，顯示最高流速為平均流速之1.38至1.45倍，且最高流速於矩形底堰在主堰堰口靠近底部兩側位置，於三角底堰在主堰堰口上方約三分之一至五分之一之過堰水頭高位置。探討中軸處流速分布，顯示側堰之面積增加，會反應到過堰流速的提昇，而且也能反應最高流速並非位於堰口底部。
本研究另外經由流線分布，分別探討表層水體及渦流範圍之流動方式，並歸納得到渦流範圍受到無因次化堰上水頭高所控制。

In this paper, Flow-3D model was applied to simulating open-channel flows over compound sharp-crested weirs. The accuracy of discharge and water level relationship from simulation with experimental results of 93 to 95% .
Analyzed compound weir section velocity distribution, plain velocity,vectors, streamline distribution, we find out the three dimensional fluent characteristic. Maximum flow velocity of 1.38 to 1.45 times the average velocity, the maximum velocity at the sides of the main weir bottom position, and triangular weir at the top end of the main weir weir to about one-third of the fifth over the weir head high position. Discussion the middle axis velocity distribution, the max and average velocity would increase with the area of side weir.
We know the flow path of surface and the area of vortex water by streamline distribution. The range of vortex control by dimensionless head over the weir.

1. 中興工程顧問社 (2014)，環境計算流體力學應用推廣及整合計畫—水利工程應用。
2. 杜王芳與趙振興 (2008)，複式斷面河道三維水流數值模擬，中國河海大學。
3. 詹錢登、張家榮、蔡長泰 (2005)，複合斷面銳緣堰量公式之研究，中國土木水利工程學刊，第十七卷第四期，703-709。
4. 農田水利會 (2007)，量水設備及量測方法。
5. Arvanaghi H. and Oskuei N. N. (2011) Sharp-Crested Weir Discharge Coefficient. Journal of Civil Engineering and Urbanism, 3(3), 87-91.
6. Flow-3D (2008). FLOW-3D User Manual Version v9.3 Flow Science, Inc..
7. Jan, C. D., Chang, C. J., and Lee, M. H. (2006) Discussion of ”Design and Calibration of a Compound Shape-Crested Weir” by J. Martinez, J. Reca, M.T. Morillas, and J.G. Lopez. Journal of Hydraulic Engineering ASCE, 132(8), 868-871.
8. Kandaswamy, P. K., and Rouse, H. (1957) Characteristics of Flow Over Thrminal Weirs And Sills. Journal of the Hydraulics ASCE, Division, 83(4), 1-13.
9. Martinez, J., Reca, J., Morillas, M. T. and Lopez, J. G. (2005) Design and Calibration of a Compound Shape-Crested Weir. Journal of Irrigation and Drainage Engineering, 131, 112-116.doi:10.1061/0733-9429.
10. Qu, J., Ramamurthy, A. S., Tadayon, R. and Chen, Z. (2009) Numerical simulation of sharp-crested weir flows. Journal of Materials in Civil Engineering, 36,1530-1534. Doi:10.1139/L09-067.
11. Rehbock, T. (1929) Wassermessung mit scharfkantigen Überfallwehren, Flußbaulaboratorium der Techn. Hochschule.
12. United States. Army. Corps of Engineers. (1952) Corps of Engineers Hydraulic Design Criteria, Waterways Experiment Station.
13. United States. Department of the Interior Bureau of Reclamation. (2011) WATER MEASUREMENT MANUAL. Retrieved from http://www.usbr.gov/pmts/hydraulics_lab/pubs/wmm/
14. Yen, B. C. (1911) Channel flow resistance: centennial of Manning's formula, Water Resources Publications LLC.