本文旨在探討波流通過排放口之淘刷深度。排放口模型建立於台南水工試驗所平面水池，在23組試驗中，分為純波、純流、波流互制、排放口排水(有噴流)等四種狀況，分別探討波、流或噴流對地形最大沖刷深度與沖刷範圍的影響。
實驗結果顯示，純流狀況下，流速越大其最大沖刷深度與沖刷範圍越大，在24小時後最大沖刷深度即達穩定；純波狀況下，KC number越大最大沖刷深度與沖刷範圍越大，在前4個小時即會達到最大值，而4小時後地形有全面沖刷造成全地形破壞，無法判定最大沖刷是否為排放口因素造成；波流互制狀況下，其沖刷地形較接近純流狀況；有噴流的狀況下單純與波或流一起較無噴流的最大沖刷來的大，但當波、流與噴流三者一起出現時，其最大沖刷深度較波流互制來的小。

The main purposes of this study are to investigate the scour depth after current and wave passing through the discharge head. The test is conducted in Tainan Hydraulic Laboratory. There are 23 tests including pure wave, pure current, and combined wave and current. Some of the tests condition have additional jet flow.
The results show when pure current passing through discharge head, the maximum scour depth and scour area achieve steady after 24 hours. When pure current passing through discharge head, the scour depth and scour area achieve maximum after 4 hours. Before 4 hours, we can’t distinguish general scour and local scour. The maximum scour depth and scour area increase when KC number increase. The scour topography of combined wave and current is similar to pure current. When pure current or pure wave get aditional jet flow, the scour depth and scour area is larger than without jet flow. Combined wave, current, and jet flow, which get less scour depth than combined wave and current.

1. 「通霄電廠更新擴建計畫」──取、排水頭及管線埋設水工模型試驗，國立成功大學水工試驗所，民國一百零一年四月。
2. Hamill, L” Bridge Hydraulics” E & F Spon, London and New York, 1999
3. Kao-Shu Hwang, Hsin-Hung Chen, and Hwung-Hweng Hwung” On the stability of a submerged discharge head under waves” Asian and Pacific Coasts , 2005 September 4-8
4. M. Ram Babu, V. Sundar, and S. Narasimha Rao” Measurement of sea bed scour around a pile-simplified instrumentation”IEEE (1998)
5. Ming Zhao , Liang Cheng, and Zhipeng Zang” Experimental and numerical investigation of local scour around a submerged vertical circular cylinder in steady currents” Coastal Engineering 57, 709–721 (2010)
6. Oumeraci, H.”Scale effects in coastal htdraulic models. Symposium on Scale Effects in Modelling Hydraulic Structures” Esslingen (1984)
7. Raudkivi, A. J., and Ettema, R., "Clear water scour at cylindrical Piers,"Journal of the Hydraulics Division, ASCE, Vol. 109, No. HY3, pp.338-350. Mar (1983)
8. Subhasish Dey, Rajkumar V. Raikar, and Abhishek Roy” Scour at Submerged Cylindrical Obstaclesunder Steady Flow” Journal of Hydraulic Engineering, Vol. 134, No. 1, January 1 (2008)
9. Sumer, B. M., Fredsøe, J., and Christiansen, N.. ‘‘Scour around a vertical pile in waves.’’ J. Wtrwy., Port, Coast., and Oc. Engrg., ASCE, 118(1), 15–31(1992)
10. Sumer, B. M. and Fredsøe, J.” Scour around pile in combined waves and current” Journal of Hydraulic Engineering, Vol. 127, No. 5(2001)