摘要
在低雷诺数圆柱绕流中,卡门涡街中涡的形状随着其向下游的发展是不断变化的,而且它也不是理想轴对称的.针对该问题,利用有限元法进行数值模拟,研究了由涡量等值线表示的涡的形状特征.由流场中几种等值线的对比可以得到,主要是涡量等值线与压力等值线之间的差异造成了涡的形状变化.利用广义的茹柯夫斯基变换描述涡相对于轴对称的变形状态.结果表明,描述涡的主要3个参数随半径的变化规律不同,即椭圆率的抛物形分布,偏心率的线性分布和弯度的近似常量的分布.在此基础上给出了3个参数各自对应的运动学量表达式,两者对比的结果还是比较相符的.
In low-Reynolds-number flow past circular cylinder, the shape of vortices in the vortex street is not ideally axisymmetrie,and changes with the the flow downstream. To solve the problem,finite element method was used to simulate the flow and the character of the vortex shape was analyzed by vorticity contour. Through analysis of a few contours, the vorticity contour changes due to the difference between the vorticity contour and the pressure contour. Generalized Joukowski transformation was used to describe the deformation of the vortex from axisymmetry. The result tive ways,namely elllipticity varies parabo shows that three parameters describing the vortex change in respeclieally, eccentricity varies linealy and bending angle is nearly constant. Kinematic expressions corresponding the three parameters were brought forward,comparison of the two expressions is satisfactory.
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2009年第6期758-761,共4页
Journal of Beijing University of Aeronautics and Astronautics
关键词
涡街
圆柱
非定常流
数学变换
vortex street
circular cylinder
unsteady flow
mathematical transformations
