前台阶分离流中柔性薄膜变形与流固耦合研究  

Research of deformation and fluid-structure interaction of flexible film in forward-facing step separation flow

作　　者：林艺鹏 薛晓鹏 王汉封[1,3] LIN Yipeng;XUE Xiaopeng;WANG Hanfeng(School of Civil Engineering,Central South University,Changsha 410075,China;School of Automation,Central South University,Changsha 410075,China;National Engineering Research Center for High-speed Railway Construction Technology,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学自动化学院,湖南长沙410075 [3]中南大学高速铁路建造技术国家工程研究中心,湖南长沙410075

出　　处：《中南大学学报(自然科学版)》2025年第3期1053-1063,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52078505);湖南省自然科学基金面上项目(2022JJ30736)。

摘　　要：通过任意拉格朗日-欧拉数值模拟方法,研究不同量纲一弯曲刚度γ的二维薄膜在前台阶分离流中的变形、拍动及相应的流固耦合特性。薄膜特征长度与台阶高度相同,基于来流速度和薄膜长度的雷诺数为640,γ由0.9000至0.0001逐渐减小。研究结果表明:当0.700≤γ≤0.900(区间Ⅰ)时,薄膜处于稳定小幅弯曲状态;当0.080<γ<0.700(区间Ⅱ)时,自由端开始出现小幅摆动,运动轨迹为往复直线运动,当0.300≤γ<0.700时,薄膜拍动频率随γ减小逐渐接近理论固有频率,之后远离固有频率;当0.060≤γ≤0.080(区间Ⅲ)时,流体力与薄膜自身恢复力接近平衡,薄膜重新回到稳定状态;当0.001≤γ<0.060(区间Ⅳ)时,薄膜发生大幅波浪式拍动,产生周期性脱落的拍动诱导涡,拍动频率随γ减小而减小;当γ从0.001继续减小至0.0001(区间Ⅴ)时,薄膜最终出现临近贴壁现象。其中,在区间Ⅰ、Ⅱ、Ⅲ和Ⅳ,薄膜能显著提高前台阶上表面回流区高度;在区间Ⅳ,薄膜波浪式拍动显著抑制了台阶上表面的分离流,台阶上表面压力系数显著减小;在区间V,薄膜几乎无法对台阶流场产生影响。研究结果可为利用薄膜控制分离流流动提供参考。Through the arbitrary Lagrangian-Eulerian numerical simulation method,the flapping dynamics and corresponding fluid-structure coupling characteristics of two-dimensional films at different dimensionless bending stiffnesses(γ)in the forward-facing step(FFS)separation flow were investigated.The characteristic length of the film was the same as the step height,the Reynolds number based on the inflow velocity and film length was 640,andγgradually decreased from 0.9000 to 0.0001.The results show that when 0.700≤γ≤0.900(range Ⅰ),the film displays a small bending stable range.When 0.080<γ<0.700(range Ⅱ),the free end of film displays a small swing,and the motion trajectory is a cyclical linear motion,the flapping frequency gradually approaches the theoretical natural frequency as γ decreases from 0.300 to 0.700,and then moves away from the natural frequency.When 0.060≤γ≤0.080(range Ⅲ),the fluid force is balanced with elastic force,and film returns to the stable range.When 0.001≤γ<0.060(range Ⅳ),the film flaps in a large wave-like manner,generates flapping-induced vortices periodically,and the flapping frequency decreases whenγdecreases.When γ from 0.001 decreases to 0.0001(range Ⅴ),the film finally adheres to the step wall.In the range Ⅰ,Ⅱ,Ⅲ and Ⅳ,the films'regim can significantly increase the height of the reflow zone on the upper surface of the front step,the wave-like flapping of the flims in range Ⅳ significantly inhibits the separation flow on the step upper surface,and the pressure coefficient of the step upper surface is significantly reduced.The flim in range Ⅴ has almost no impact on the step flow field.The research can provide references for using films to control separation flow.

关 键 词：任意拉格朗日-欧拉法(ALE) 前台阶分离流 柔性薄膜 量纲一弯曲刚度 流动控制 

分 类 号：TU971[建筑科学—建筑理论]