圆盘绕流近尾迹相干结构大涡模拟  

Study on Coherent Structure in the Near Wake of a Circular Disk by LES

作　　者：钟伟[1] 杨渐志[1] 张新太[1] 刘泉[1] 刘明侯[1] 

机构地区：[1]中国科学技术大学热科学和能源工程系,合肥230027

出　　处：《工程热物理学报》2015年第2期308-312,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.11172296;No.50936005)

摘　　要：对Re=22000圆盘近尾迹进行大涡模拟数值研究,通过对x/D=1,4处径向多点脉动速度进行快速傅里叶变换（FFT）,发现三个特征频率,其对应的Strouhal数分别为0.035、0.123和1.3¹.7。分析表明,St₂=0.123为涡旋自然脱落频率,与文献结果相符;较小频率St₁=0.035,可能与回流区伸缩和剪切层附近涡旋脱落点周向旋转共同作用相关;而高频率St₃=1.3¹.7则与剪切层结构相关。最后对圆盘近尾迹流场作特征正交分解（POD）,根据1⁶模态的分布,分析大尺度结构的可能存在形式。LES investigation was conducted in the near wake behind a circular disk at Re = 22,000.Through FFT of fluctuating velocities of several points at x/D=1,4,three characteristic frequencies with Strouhal numbers of 0.035,0.123 and 1.3~1.7 were detected.Results showed that St_2 = 0.123,was the natural vortea;shedding frequency,which was in accord with previous research results;St_1 = 0.035,the smaller one,could be relevant to the combination of the recirculation zone's pulsation and the shedding location's rotation near the shear layer;St_3 = 1.3 ~ 1.7,could result from the instability of the shear layer.Finally,proper orthogonal decomposition(POD) was performed in a disk's near wake,its large-scale structure was studied based on 1~6 POD modes.

关 键 词：圆盘钝体 近尾迹 大涡模拟 特征正交分解 

分 类 号：O357.5[理学—流体力学]