Onset of instability of a flag in uniform flow  

作　　者：Fangbao Tian Xiyun Lu Haoxiang Luo 

机构地区：[1]Department of Modern Mechanics,University of Science and Technology of China,Hefei,Anhui 230026,China [2]Department of Mechanical Engineering,Vanderbilt University,2301 Vanderbilt Place,Nashville,Tennessee 37235-1592,USA

出　　处：《Theoretical & Applied Mechanics Letters》2012年第2期59-63,共5页力学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (10832010);the Innovation Project of the Chinese Academy of Sciences (KJCX2-YW-L05);the United States National Science Foundation(CBET-0954381)

摘　　要：This paper numerically and analytically studies the onset of instability of a flag in uniform flow. The three-dimensional （3D） simulation is performed by using an immersed-boundary method coupled with a nonlinear finite element method. The global stability, bistability and instability are identified in the 3D simulations. The Squire＇s theorem is extended to analyze the stability of the fluid-flag system with 3D initial perturbations. It is found that if a parallel flow around the flag admits an unstable 3D disturbance for a certain value of the flutter speed, then a two-dimensional （2D） disturbance at a lower flutter speed is also adnfitted. In addition, the growth rate of 2D disturbance is larger than that of the 3D disturbance.This paper numerically and analytically studies the onset of instability of a flag in uniform flow. The three-dimensional （3D） simulation is performed by using an immersed-boundary method coupled with a nonlinear finite element method. The global stability, bistability and instability are identified in the 3D simulations. The Squire＇s theorem is extended to analyze the stability of the fluid-flag system with 3D initial perturbations. It is found that if a parallel flow around the flag admits an unstable 3D disturbance for a certain value of the flutter speed, then a two-dimensional （2D） disturbance at a lower flutter speed is also adnfitted. In addition, the growth rate of 2D disturbance is larger than that of the 3D disturbance.

关 键 词：flag instability fluid-structure interaction immersed-boundary method Squire＇s theorem 

分 类 号：TN101[电子电信—物理电子学] TV133.1[水利工程—水力学及河流动力学]