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1.3<sup>1</sup>.7。分析表明,St<sub>2</sub>=0.123为涡旋自然脱落频率,与文献结果相符;较小频率St<sub>1</sub>=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St<sub>3</sub>=1.3<sup>1</sup>.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1<sup>6</sup>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.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
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)
