拉格朗日方法下立方体诱导拟序结构的实验  

TR PIV INVESTIGATION ON THE LAGRANGIAN HAIRPIN VORTICES INDUCED BY A CUBIC DISTURBANCE

作　　者：权基琢鋆[1] 姜楠[2,3] 唐湛棋[2] 

机构地区：[1]天津市特种设备监督检验技术研究院,天津300192 [2]天津大学机械工程学院力学系,天津300072 [3]天津市现代工程力学重点实验室,天津300072

出　　处：《力学学报》2013年第5期772-776,共5页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(11332006;11272233);国家重点基础研究发展计划(973计划)(2012CB720101);中国科学院力学研究所非线性国家重点实验室对外开放课题联合资助项目~~

摘　　要：运用时分粒图仪(time-resolved particle image velocimetry)对平板边界层中立方体扰动诱导产生的发卡涡涡结构进行了实验测量,得到了立方体扰动尾迹区中展向平面内的速度矢量分布.基于拉格朗日坐标系,运用李亚普诺夫指数对流场中的相干结构进行了辨识,比较欧拉坐标系下的结果发现拉格朗日体系下李亚普诺夫指数场不仅有效地包含欧拉坐标系下涡强所表征的发卡涡涡头信息外,并且能够呈现出涡颈在空间中的分布,能够完全刻画出发卡涡涡结构在展向平面内的信息,还发现李亚普诺夫指数对流场拟序结构的表征有很好的鲁棒性.另外,李亚普诺夫指数场的互相关分析表明诱导产生的发卡涡涡结构随着向下游的传播,其涡头不断抬升,发卡涡涡结构与壁面的倾角也逐渐变大,有效地刻画了拟序结构的空间演化过程.The hairpin vortices structure induced by a cubic disturbance with a frequency of 2.1 Hz are investigated by time-resolved particle image velocimetry （TR PIV） from both the Euler and Lagrangian view. Firstly, the hairpin vortices＇ heads could be clearly distinguished form the side-view database, which also indicates that the hairpin heads lift up when convecting down streamwise. Then, the finite-time lyapunov exponents （FTLE） method is utilized to describe the lagrangian hairpin vortices induced by the cubic. It could be seen that FTLE clearly shows both the projection of the hairpin heads and the hairpin necks in the streamwise and spanwise plane. Furthermore, two-point correlation of FTLE at different reference positions along the streamwise indicate that the hairpin vortices statistically with an increasing inclined angle with the fiat plate while they are moving downstream.

关 键 词：拉格朗日拟序结构 李亚普诺夫指数 立方体扰动 时分粒图仪 

分 类 号：O357.52[理学—流体力学]