摘 要
本研究以實驗方式來探討排放角度和底床邊界對單管浮昇射流之影響。實驗在一靜止的水槽中以台車拖曳排放鹽水的射流管來模擬橫向流場中的浮昇射流，實驗採用雷射引致螢光法配合CCD攝影機以連續擷取射流之影像，經由影像處理可得射流的軌跡和濃度場。實驗結果顯示：在無邊牆效應、有橫向流的狀況下，於同一下游距離，排放角度愈大，則射流的稀釋率會愈大。當豎管接近底床時，角度變化是否產生附著現象，由排放角度與豎管高度決定。若排放角度 時，附著現象便會發生，然而散佈係數會隨著橫向流流速的增加而變小。當附著現象發生時，邊界會抑制浮昇射流的混合，導致射流的稀釋情形變差。實驗結果並與美國環保署所發展之模式CORMIX比較，發現該模式無法準確地預測邊界效應及附著現象的稀釋情形。本研究之結果可供設計海洋放流管的排放角度參考。

Abstract
An experimental study of discharge angle and boundary effect on buoyant jets is presented. The experimental setup comprises a towed single jet discharging salt water into a laboratory tank with a horizontal plexiglass plate close to the diffuser port. Trajectories and concentration distributions of buoyant jets were measured by the planner laser-induced fluorescence (PLIF) method. It was found, due to the Coanda effect, buoyant jets will cling to the boundary when discharge angle , where β is the spreading coefficient. This phenomenon has a marked effect on the jet trajectory and its near-field dilution. Results of this study also showed that the near-field model CORMIX fails to predict above phenomenon.

參考文獻
Albertson M. L. Dai, Y. B., Jensen, R. A. and Rouse, H., "Diffusion of submerged jets", Trans. Am. Soc. Civ. Engrs., 115, pp.639-697 (1950)
Arcoumanis, C., McGuirk, J.J. and Palma, J.M.L.M., "On the use of fluorescent dyes for concentration measurements in water flows", Experiments in Fluids, 10, pp.177-180 (1990)
Catrakis, H.J. and Dimotakis, P.E., "Mixing in turbulent jets: scalar measures and iso-surface geometry", Journal of Fluid Mechanics, Vol. 317, pp.369-406 (1996)
Cheng, C.W., Davidson, M.J. and Wood, I.R., "Merging buoyant discharges in an ambient current", Journal of Hydraulic Research, Vol. 30, No. 3, pp.361-372 (1992)
Chu, V.H., Discussion of “Mean behavior of buoyant jets in a crossflow” by S.J. Wright, Journal of the Hydraulics Division, ASCE, Vol.104, pp.318-320, (1978)
Dahm, W.J.A. and Dimotakis, P.E., "Measurement of entrainment and mixing in turbulent jets", AIAA, Vol. 25, No. 9, pp.1216-1223 (1987)
Davis, M.R. and Winarto, H., "Jet diffusion from a circular nozzle above a solid plane", Journal of Fluid Mechanics, Vol. 101, Part 1, pp.201-221 (1980)
Doneker, R.L. and Jirka, G.H., "CORMIX 1: An expert system for mixing zone analysis of conventional and toxic single port aquatic discharges", USEPA, Athens, GA. (1990)
Ferrier, A.J., Funk, D.R. and Roberts, P.J.W., "Application of optical techniques to the study of plumes in stratified fluids", Dynamics of Atmospheres and Oceans, 20, pp.155-183 (1993)
Hirst, E.A., "Buoyant jets with three-dimensional trajectories", J. of Hydraulics Div., ASCE, Vol. 98, pp.1999-2013 (1972)
Jirka, G.H. and Doneker, R.L., "Hydrodynamic classification of submerged single-port discharges", Journal of Hydraulic Engineering, ASCE, Vol. 117, No. 9, pp.1095-1112 (1991)
Jirka, G.H., Doneker, R.L. and Hinton, S.W., "User’s Manual for CORMIX: A Hydrodynamic Mixing Zone Model and Decision Support System for Pollutant Discharges into Surface Water", DeFrees Hydraulics Laboratory, Cornell University, Ithaca, NY, (1996)
Knudsen, M. and Wood, I.R., "The interaction between a boundary and a horizontal buoyant jet", Journal of Hydraulic Research, Vol. 28, No. 3, pp.375-385 (1990)
Koh, R.C.Y. and Brooks, N.H., "Fluid mechanics of waste-water disposal in the ocean", Ann. Rev. Fluid Mech., Vol. 7, pp.187-211 (1975)
Launder, B.E. and Rodi, W., "The turbulent wall jet - measurement and modeling", Ann. Rev. Fluid Mech., Vol. 15, pp.429-459 (1983)
Lee, J.H.W. and Neville-Jones, P., "Sea outfall design-prediction of initial dilution", Proc. Instn. Civ. Engrs., Part 1, 82, pp.981-994 (1987)
Lemoine, F., Wolff, M. and Lebouche, M., "Simultaneous concentration and velocity measurements using combined laser-induced fluorescence and laser Doppler velocimetry : Application to turbulent transport", Experiments in Fluids, 20, pp.319-327 (1996)
List, E.J., "Turbulent jets and plumes", Ann. Rev. Fluid Mech., Vol. 14, pp.189-212 (1982)
Morton, B., Taylor, G.I. and Turner, J.S., "Turbulent gravitational convection form maintained and instantaneous sources", J. of the Royal Society, London, England, A234. (1956)
Papanicolaou, P.N. and List, E.J., "Investigations of round vertical turbulent buoyant jets", Journal of Fluid Mechanics, Vol. 195, pp.341-391 (1988)
Rapps, D.A. and Wood, I.R., "Accurate measurement of concentrations in buoyant jets using planar laser-induced fluorescence", submitted to Journal of Hydraulic Research (1996)
Roberts, P.J.W., "Line plume and ocean outfall dispersion", J. of Hydraulics Div., ASCE, Vol. 105, No. HY4, pp.314-331 (1979)
Sharp, J.J. and Vyas, B.D., "The buoyant wall jet", Proc. Instn. Civ. Engrs., Part 2, 63, pp.593-611 (1977)
Shih, C., Krothapalli, A. and Gogineni, S., "Experimental-Observations of Instability Modes in a Rectangular Jet", AIAA, Vol 30, No. 10, pp. 2388-2394 (1992)
Sobey R.J., Johnston, A.J. and Keane, R.D., "Horizontal round buoyant jet in shallow water", Journal of Hydraulic Engineering, Vol. 114, No. 8, pp.910-929 (1988)
Wood, I.R., Bell, R.G. and Wilkinson, D.L., "Ocean disposal of wastewater", World Scientific Inc. (1993)
Wright, S.J. "Mean behavior of buoyant jets in a crossflow", J. of Hydraulics Div., ASCE, Vol. 103, No. HY5, pp.499-513 (1977)
梁天堯, “橫向流場中浮昇射流軌跡之實驗研究”, 中央大學土木工程研究所碩士論文, 1996
李坤樹, “以雷射引致螢光法研究邊牆效應對浮昇射流之影響”, 中央大學土木工程研究所碩士論文, 1997
詹國華, “紊流橫向流對浮昇射流影響之實驗研究”, 中央大學土木工程研究所碩士論文, 1997