本論文主要探討圓柱管噴流在靜止流體中的特性以及圓柱管噴流在橫流中的噴流軌跡分析。本實驗在封閉式垂直橫流水洞進行，分別藉由流場可視化以及質點影像速度儀 (P.I.V.) 觀察流場結構。

圓柱管噴流在靜止流體中的特性中，探討層流範圍時，不同雷諾數下，空間參數對於噴流流量的改變以及噴流中心線速度衰減的特性。質點影像速度儀使用兩個不同的計算解析度分析擷取的影像。當使用較小的解析度時，分析結果較為接近理論模型的估算。實驗結果顯示，渦流環的產生對噴流的流量及速度造成顯著的改變。噴流出口速度剖面的衍化結果顯示，渦流環產生之後的速度剖面接近 Schlichting 理論的速度分布。

圓柱管噴流在橫流中實驗結果的軌跡分析顯示，以流線、速度及渦度方式定義的三種噴流軌跡在速度比小於3及大於9時有較明顯的差異。本研究以流線軌跡分析噴流軌跡在橫流環境下的表現，分別以相同速度比以及相同橫流速度兩種條件比較噴流軌跡的改變，實驗結果顯示，雷諾數為主要影響噴流軌跡的參數，當噴流雷諾數在層、 紊流過渡區域時，噴流軌跡有轉折的現象。當噴流雷諾數越接近紊流區域時，噴流軌跡越接近過去文獻的經驗公式。

The research studies the features of round tube jets in a stationary environment and the trajectory analysis of round tube jets in a cross-flow environment. The experiments were carried out in a vertical closed-loop water tunnel. Flow structures were observed by using flow visualization and Particle Image Velocimetry(P.I.V.) techniques respectively.

For round tube jets in a stationary environment, the characteristics of the flow rate and the maximum axial velocity are different for the round tube jets having different Reynolds numbers. Particle Image Velocimetry uses two interrogation cells to analyze captured images. A finer cell has results approaching to the theoretical model. Experimental results show that, the vortex ring formation changes the flow rate and the velocity field of the jet significantly. The velocity profile of the jet is closer to that of Schlichting theory after the vortex ring formation.

For the trajectory analysis results of round tube jets in a cross-flow environment, three different trajectories determined by streamline, velocity and vorticity are notably different when the velocity ratio is less than 3 or larger than 9. This research uses streamline trajectory to analyze a round tube jet in a cross-flow environment. Experimental data are analyzed under two specific conditions of the same velocity ratio and the same cross-flow velocity. Experimental results show that Reynolds number is an important index for jet trajectory for these two conditions. When the Reynolds number of the jet is in the transition region, the trajectory of the jet shows some changes, especially the maximum axial distance which the jet can reach. When the Reynolds number is in the turbulent region, the jet trajectory is similar to those reported in the previous literature.

[1] 楊盛翔, 不同動量通量比的水平圓柱管噴流在垂直橫流中交互作用之實驗研究, 國立台灣科技大學機械工程學系, 碩士學位論文, 民國一百年七月。
[2] McNaughton, K. J. & Sinclair, C. G., Submerged jets in short cylindrical flow vessels, Journal of Fluid Mechanics, 25 (1966), 367-375.
[3] Xia, L. P. & Lam, K. M., Velocity and concentration measurements in initial region of submerged round jets in stagnant environment and in coflow, Journal of Hydro-environment Research, 3 (2009), 21-34.
[4] Kwon, S. J. & Seo, I. W., Reynolds number effects on the behavior of a non-buoyant round jet, Experiments in Fluids, 38 (2005), 801-812.
[5] Schlichting, H., Boundary layer theory, 7th edition, McGraw-Hill Publishers, ISBN 0-07-055334-3, (1979).
[6] Lee, D. S., Kihm, K.D. & Chung, S. H., Analytical solutions for the developing jet from a fully-developed laminar tube flow, ASME Journal of Fluids Engineering, 119 (1997), 716-718.
[7] Rankin, G. W. & Sridhar, K., Developing region of laminar jets with parabolic exit velocity profiles, ASME Journal of Fluids Engineering, 103 (1981), 322-327.
[8] Rankin, G. W., Sridhar, K., Arulraja M. & Kumar K. R., An experimental investigation of laminar axisymmetric submerged jets, Journal of Fluid Mechanics, 133 (1983), 217-231.
[9] Giralt, F., Chia, C. J. & Trass, O., Characterization of the impingement region in an axisymmetric turbulent jet, Industrial and Engineering Chemistry Fundamentals, 16(1) (1977), 21-28.
[10] New, T. H., Lim, T. T. & Luo, S. C., Effects of jet velocity profiles on a round jet in cross-flow, Experiments in Fluids, 40 (2006), 859-875.
[11] New, T. H., Lim, T. T. & Luo, S. C., A visual study on elliptical jets in cross flow, Journal of Visualization, 5(2) (2002), 129-136.
[12] Huang, R. F. & Hsieh, R. H., An experimental study of elevated round jets deflected in a crosswind, Experimental Thermal and Fluid Science, 27 (2002), 77-86.
[13] Kamotani, Y. & Greber I., Experiments on a turbulent jet in a cross flow, AIAA Journal, 10(11) (1972), 1425-1429.
[14] Karagozian, A. R., An analytical model for the vorticity associated with a transverse jet, AIAA Journal, 24(3) (1986), 429-436.
[15] Su, L. K. & Mungal, M. G., Simultaneous measurements of scalar and velocity field evolution in turbulent crossflowing jets, Journal of Fluid Mechanics, 513 (2004), 1-45.
[16] Margason, R. J., Fifty years of jet in crossflow research, Computational and Experimental Assessment of Jets in Cross Flow, AGARD-CP-534 (1993).
[17] Yuan, L. L. & Street, R. L., Trajectory and entrainment of a round jet in crossflow, Physics of Fluids, 10 (1998), 2323-2335.
[18] 蘭真, 偏折噴流之剪流層渦漩動力機制與紊流特性, 國立台灣科技大學機械工程學系, 博士學位論文, 民國九四年十月。
[19] 張智超, 設置垂直式水洞圓管噴流實驗, 國立台灣科技大學機械工程學系, 碩士學位論文, 民國九十八年七月。
[20] 賴元偉, 圓柱管噴流於垂直式水洞的實驗研究, 國立台灣科技大學機械工程學系, 碩士學位論文, 民國九十九年七月。
[21] Hasselbrink JR, E. F. & Mungal, M. G., Transverse jets and jet flames. Part 1. Scaling laws for strong transverse jets, Journal of Fluid Mechanics, 443 (2001), 1-25.
[22] Fischer, H. B., List, E. J., Koh, R. C. Y., Imberger, J. & Brooks, N. H., Mixing in inland and coastal waters, ACADEMIC PRESS, ISBN 0-12-258150-4, (1979).
[23] Lee, J. H. W. & Chu, V. H., Turbulent jets and plumes: a Lagrangian approach, Kluwer Academic Publishers, ISBN 1-4020-7520-0, (2003).
[24] Tropea, C., Yarin, A. L. & Foss, J. F., Springer handbook of experimental fluid mechanics, Springer, ISBN 978-3-540-25141-5, (2007).