中文摘要：

利用溢流恒压装置产生具有稳定出流速度的圆管潜射流,结合染色液流态显示方法,在多种射流无量纲潜深d/H、雷诺数Re以及限制数C的组合下,实验研究了该潜射流动量在有限深密度均匀流体中的演化特性,其中d为射流潜深,H为水深.研究表明,当C〈1时潜射流表现为深水特征,而当16C〈2时潜射流表现为过渡特征,在这两种情况下均不产生任何形式的大尺度相干结构；当26 C〈10时潜射流表现为浅水特征,而C〉10时潜射流表现为极浅水特征,在这两种情况下均产生大尺度的偶极子涡结构.对极浅水特征潜射流,在各种无量纲潜深下,偶极子涡结构的无量纲形成时间t＊f 与无量纲射流时间Ti＊nj均满足相同的正比例关系；对浅水特征潜射流,当d/H=0.5时, t＊f 与Ti＊nj满足某种线性关系,但对其他无量纲潜深, t＊f 与Ti＊nj之间无明显规律.

英文摘要：

The formation mechanism and evolution characteristics of a submerged round jet in a uniform fluid of finite depth are investigated experimentally. A spillover system is designed to produce a continuous horizontal jet in the background fluid with a constant velocity, and the flow is visualized by the dyed liquid. Experiments are conducted under different combinations of Reynolds number Re, confinement number C and nondimensional draft d/H , where d is the vertical distance from the jet to the free surface, and H is the depth of the ambient fluid. Four flow patterns are identified for various C. When C〈1, the jet shows a deep-water pattern, while for 1 6 C〈2, it shows the transitional pattern, the jets do not develop a structured flow for the two jet patterns. When 2 6 C〈10, the jet shows the shallow-water pattern, while if C〉10, the jet shows the extreme-shallow-water pattern. In both these two patterns, the jets generate vortex dipole structures. In the extreme-shallow water pattern, the nondimensional vortex formation time t＊f for the vortex dipole structure is proportional to the nondimensional injection time Ti＊nj for various draft d/H . In the shallow-water pattern, t＊f depends linearly on Ti＊nj Re1/2 when the draft d/H=0.5;however, there is no observable relationships between t＊f and Ti＊nj for other draft d/H .