风洞实验中翼型大迎角气动力分散性的机理分析

基于$k$-$\omega$的SST两方程湍流模型, 求解雷诺平均N-S方程获得定常和非定常气动力, 耦合 翼型弹性振动方程, 在时间域内模拟了不同的翼型非定常流动, 重点研究了大迎角下的分离 流问题, 研究结果表明: 在百万雷诺数条件下, 由于振动引起分离涡的不规律脱落, 可能导 致气动力平均值的变化; 而厚度大于20\%的翼型在一定大迎角范围内, 会出现分离涡流场平 衡态的转化, 从流体力学稳定性的角度, 解释了风洞实验中大迎角气动力数据的分散性, 为 大迎角气动力风洞实验的重复性和数据分散性给出了一种新解释.

PHYSICAL ANALYSIS OF SCATTERED AERODYNAMIC FORCES OF AIRFOILS WITH HIGH INCIDENCE IN WIND-TUNNEL EXPERIMENTS

Based on the Reynolds-Averaged Navier-Stokes equations with $k$-$\omega$ SST turbulent model and coupled with the motion equations for an elastic supported system, the steady and unsteady flows for airfoils with different incidences are simulated, specially, for high incidences when separated vortices exist. For the given Reynolds numbers and structure parameters considered in this paper, the frequencies of shedding vortex have a complicated relation with the airfoil vibration. The average aerodynamic force may vary for some forced vibrations. For airfoils with thickness larger than 20{\%}, the aeroelastic response can lead to a separated flow field from one balance state to another so that the aerodynamic force changes from one value to another. These results can explain the poor repeatability of experimental results in these regions.