摘要
本文试对后台阶流动及其控制研究的进展进行综述.首先,试图归纳来流条件与几何参数对后台阶流动的分离泡长度、壁面压力系数、壁面摩擦系数、速度分布及雷诺应力分布的影响.其次,总结了后台阶流动的非定常特性,并结合作者自己的研究工作,发现后台阶流动由SL模态(Shear Layer Mode)和SD模态(Shedding Mode)主导,前者又包含K-H不稳定性(Kelvin-Helmholtz Instability)、涡配对(Vortex Pairing)和ST模态(Step Mode).此外,后台阶流动低频特性包括剪切层的摆动(Flapping)和再附位置的振荡(Oscillating),由剪切层中拟序结构与壁面相互作用导致.最后,回顾了后台阶激励流动的相关研究,提炼出了减小分离泡长度的最优激励频率St_h≈0.2?,并对该频率作出了物理解释.
This article reviews the development of research work on backward-facing step flow and separation reduction techniques. Firstly, the effects of inflow conditions and geometry parameters on the bubble length, pressure coefficient, skin friction coefficient, velocity profiles and profiles of Reynolds stresses of the backward-facing step flow are identified. Secondly, we find that the unsteadiness of backward-facing step flow is dominated by shear layer mode and shedding mode, the former including Kelvin-Helmholtz instability, vortex pairing and step mode. Furthermore, the lower-frequency characteristics are consist of shear layer flapping and reattachment oscillating, resulting from the interaction between the coherent structures in the shear layer and the wall. Finally, the flow control practice on the backward-facing step flow has also been discussed. It is found that the recirculating bubble length can be significantly reduced with appropriate excitation frequency in the harmonic excitation practice. The optimum excitation frequency, Sth, is of about 0.2, and a physical explanation is given by the authors.
出处
《中国科学：物理学、力学、天文学》
CSCD
北大核心
2015年第12期30-39,共10页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(批准号:11202115
11272183)
国家重点基础研究发展计划(编号:2014CB744801)资助项目
关键词
后台阶
时均特性
非定常特性
分离控制
backward-facing step
time-averaged characteristics
unsteadiness
separation control
