轴对称钝体前缘分离剪切层的非线性行为

董宇飞

轴对称钝体前缘分离剪切层的非线性行为

董宇飞

中国科学院力学研究所

详细信息

中图分类号: O 354.1
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出版历程
- 收稿日期: 1998-06-26
- 网络出版日期: 1998-06-30

Nonlinear Behavior of Separated Shear Layer of a Blunt Circular Cylinder

Dong Yufei

Institute of Mechanics,Chinese Academy of Sciences

摘要

摘要: 实验研究了锐前缘轴对称钝体前缘分离剪切层发展演化的动力学过程,以及分离剪切层与外加声激励之间的非线性作用.研究结果表明,自然状态下,存在着亚谐频现象,分离剪切层的演化发展是通过涡合并方式实现的.从分离到再附,层流分离剪切层一般经过2次涡合并过程,湍流分离剪切层一般经过5次涡合并过程.混沌动力学分析表明,层流分离剪切层是经过Hopf分岔和周期倍分岔途径进入混沌状态的.此外,讨论了分离剪切层对外加声激励的响应.
- 分离流动 /
- 激励 /
- 共振 /
- 锁频
Abstract: Dynamical evolution process of separated shear layer of a blunt circular cylinder,and nonlinear interaction between separated shear layer and acoustic forcing have been experimentally investigated. The researches demonstrate, in unexcited state, there exists the subharmonic phenomenon, which implies the evolution of separated shear layer is mainly through vortices merging process. From separation to reattachment, laminar separated shear layer will take 2 times vortices merging processes, and turbulence separated shear layer will experience 5 times vortices merging. From the point of view of nonlinear dynamical system, transition of separated shear layer from order to chaos is through Hopf bifurcation and periodical bifurcation. In addition, response of separated shear layer to acoustic forcing was discussed.
- separated flow /
- excitation /
- resonance /
- lock-in

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参考文献(1)

1. Ota T, Itasaka M. Separated and reattached flow on a blunt flat plate. ASME J Fluids Engng, 1976, 98:79~86 2. Kiya M, Sasaki K. Structure of a turbulent separation bubble. J Fluid Mech, 1983,137:83~113 3. Cherry N J, Hillier R, Latour M E M P. Unsteady measurements in a separated and reattaching flow. J Fluid Mech, 1984, 144:13~46 4. Sasaki K, Kiya M. Three-dimensional vortex structure in a leading-edge separation bubble at moderate Reynolds number. J Fluids Engng, 1991, 113:405~410 5. Bradshaw P, Wong F Y F. The reattachment and relaxation of a turbulent shear layer. J Fluid Mech, 1972, 52:113~135 6. Eaton J K, Johnston J P. Research on subsonic turbulent flow reattachment. AIAA J, 1981, 19(9):1093~1100 7. Ruderich R,Fernholz H H. An experimental investigation of a turbulent shear flow with separation, reverse flow, and reattachment. J Fluid Mech, 1986, 163:283~322 8. Gad-el-hak M, Blackwelder R F. On the discrete vortices from a delta wing.AIAA J, 1985, 23:961~962 9. Gad-el-hak M, Ho C M. Unsteady vortical flow around three dimensional lifting surfaces. AIAA J, 1986, 24(5):713~721[ZK)] 10. [ZK(#]Ota T. An axisymmetric separated and reattached flow on a longitudinal blunt circular cylinder. ASME J Appl Mech, 1975, 42:311~315 11. Ota T, Motegl H. Turbulence measurements in an axisymmetric separated and reattached flow over a longitudinal blunt circular cylinder. ASME J Appl Mech, 1980, 47:1~6 12. Kiya M, Mochizuki O, Tamura H, et al. Turbulence properties of an axisymmetric separation-and-reattaching flow. AIAA J, 1991, 29:936~941 13. 董宇飞.轴对称钝体分离流动及其控制:[学位论文].北京:北京大学力学系,1996

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