-
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C1时潜射流表现为深水特征, 而当1 C2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2 C10时潜射流表现为浅水特征, 而C10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tf*与无量纲射流时间Tinj*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, tf*与Tinj*满足某种线性关系, 但对其他无量纲潜深, tf*与Tinj*之间无明显规律.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 C1, the jet shows a deep-water pattern, while for 1 C2, it shows the transitional pattern, the jets do not develop a structured flow for the two jet patterns. When 2 C10, the jet shows the shallow-water pattern, while if C10, 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 tf* for the vortex dipole structure is proportional to the nondimensional injection time Tinj* for various draft d/H. In the shallow-water pattern, tf* depends linearly on Tinj*Re1/2 when the draft d/H=0.5; however, there is no observable relationships between tf* and Tinj* for other draft d/H.
-
Keywords:
- submerged round jet/
- confinement number/
- vortex dipole/
- formation time
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] -
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34]
计量
- 文章访问数:5393
- PDF下载量:727
- 被引次数:0
下载: