摘要
采用大涡模拟方法计算Re=2×10^(3)三维不等直径串列圆柱(d/D≤1)绕流问题。结果显示,处于双涡脱落流态时,随着串列圆柱间距增加,上游圆柱量纲为一的涡脱频率值St_(1)总体上升,而下游圆柱量纲为一的涡脱频率值St_(2)存在先下降后上升的变化规律。在圆柱间距较小的情况下,St_(2)随着串列圆柱间距的增加而减小,量纲为一的涡脱频率比值、直径比与间距比之间近似满足St_(2)/St_(1)∝(L/D)^(-1/4)(d/D)的幂指数关系;在圆柱间距较大的情况下,圆柱间时均流向速度提高并趋近主流区速度,St_(2)随间距比增加而上升。在较小直径比串列圆柱情形下,下游圆柱量纲为一的涡脱频率St_(2)可下降至更低的临界拐点,从而产生“次谐波涡脱锁定”现象。
The large eddy simulation method is used to simulate the three⁃dimensional flow past tandem cylinders with unequal diameters(d/D≤1)at Re=2×10^(3).In co⁃shedding regime,with tandem cylinder spacing increasing,dimensionless vortex shedding frequency of upstream cylinder(St_(1))keeps rising,and the dimensionless vortex shedding frequency of downstream cylinder(St_(2))has the change of first falling and then rising.At small spacing,St_(2) decreases with increased spacing,and dimensionless vortex shedding frequency ratio,diameter ratio and spacing ratio are in quantitative power exponent relation,St_(2)/St_(1)∝(L/D)^(-1/4)(d/D).At larger spacing,the time⁃averaged streamwise velocity between cylinders rises and approaches the main stream,and St_(2) increases with increased spacing.In tandem cylinders with smaller di⁃ameter ratio,St_(2) moves to a lower inflection point,resulting in“sub⁃harmonic lock⁃in”phenomenon.
作者
陈洁
虞培祥
欧阳华
CHEN Jie;YU Peixiang;OUYANG Hua(School of Mechanical Engineering,Shanghai Jiao Tong University,200240 Shanghai,China;Engineering Center of the Ministry of Education for Gas Turbine and Civil Aviation Engines,200240 Shanghai,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2022年第2期386-393,共8页
Chinese Journal of Applied Mechanics
基金
国家科技重大专项资助项目(No.2017-Ⅱ-0007-0021)
中国联合重燃专项资助项目(No.19UGTC037)。
关键词
不等直径串列圆柱
双涡脱落流态
三维大涡模拟
频率特征
tandem cylinders with unequal diameters
co-shedding regime
three-dimensional large eddy simulation
frequency characteristic
作者简介
通信作者:虞培祥。E⁃mail:pxyu@sjtu.edu.cn。
