两自由度平板大幅运动的气动特性与稳定性的CFD研究  

CFD investigation on aerodynamics and stability of a two degree-of-freedom thin plate undergoing large-amplitude oscillation

作　　者：祝志文 颜爽[1] 王钦华[1] 李加武[2] ZHU Zhi-wen;YAN Shuang;WANG Qin-hua;LI Jia-wu(Key Laboratory of Structure and Wind Tunnel of Guangdong Higher Education Institutes(Shantou University),Shantou 515063,China;Highway School,Chang′an University,Xi′an 710064,China)

机构地区：[1]广东省高等学校结构与风洞重点实验室(汕头大学),广东汕头515063 [2]长安大学公路学院,陕西西安710064

出　　处：《振动工程学报》2021年第2期271-282,共12页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(51878269,51978077);汕头大学卓越人才计划(NTF18014)。

摘　　要：为研究两自由度薄平板大幅运动的气动特性,评价其气动稳定性,基于任意拉格朗日‑欧拉描述法的动网格技术,通过有限差分法求解描述任意流变区域不可压流动的控制方程,开展了不同折减风速下薄平板竖弯和扭转运动绕流场的CFD(Computational Fluid Dynamics)模拟。研究认为,单自由度薄平板小幅运动的气动力系统是线性和稳定的,即使单自由度大幅竖弯运动也是线性和气动稳定的。但单自由度大幅扭转运动的平板气动力系统出现非线性,并随折减风速的提高非线性变得显著,且平板将进入气动不稳定状态。另外,大幅扭转耦合不同竖弯振幅运动的平板,气动力系统均为非线性并随折减风速的提高越加显著,而该非线性主要来自扭转自由度的大幅运动;对该两自由度耦合系统,当竖弯振幅较小和折减风速较高时,气动力系统是不稳定的;但当竖弯振幅较大时,气动力系统将是稳定的。In order to investigate the aerodynamic characteristics and aerodynamic stability of the two degree-of-freedom(2-DOF)thin plate undergoing large-amplitude oscillation,the governing equations for arbitrary-deformed fluid domain in the two-dimensional incompressible form are numerical solved based on the Arbitrary-Lagrangian-Eulerian description and the finite difference method in moving-grid system.Then,computational fluid dynamics(CFD)is employed to simulate the flow field around the thin plate undergoing heave and/or pitch oscillation at various reduced wind speeds.The research finds that the aerodynamic system around the thin plate is linear and stability when the thin plate experiences small-amplitude vibration in heave or pitch,and it is also linear and stable even when the thin plate undergoes large-amplitude heave motion.However,when the thin plate undergoes large-amplitude pitch motion,the aerodynamic system of the thin plate presents nonlinearity which will become significant and even turn into instability with the increase of reduced wind speed.Meanwhile,when the thin plate experiences 2-DOF oscillation with large amplitude in pitch coupled with different amplitude in heave,nonlinearity will also be presented and be more significant with the increase of reduced wind speed.It is noted that such nonlinearity is generated from the large-amplitude oscillation in pitch.For the coupled vibration system with 2-DOF,when the vibration amplitude is small while the reduced wind speed is high,its aerodynamic system is instable.While when the vibration amplitude in heave is large,the aeroelastic system will be stable.

关 键 词：气动稳定性 薄平板 大幅运动 CFD 气动力非线性 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] V211.3[交通运输工程—道路与铁道工程]