风洞实验中翼型大迎角气动力分散性的机理分析

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

  • 摘要: 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.

     

    Abstract: Based on the Reynolds-Averaged Navier-Stokes equations with k-\omega SST turbulent model and coupled with the motion equationsfor an elastic supported system, the steady and unsteady flows for airfoilswith different incidences are simulated, specially, for high incidences whenseparated vortices exist. For the given Reynolds numbers and structureparameters considered in this paper, the frequencies of shedding vortex havea complicated relation with the airfoil vibration. The average aerodynamicforce may vary for some forced vibrations. For airfoils with thicknesslarger than 20\%, the aeroelastic response can lead to a separated flowfield from one balance state to another so that the aerodynamic forcechanges from one value to another. These results can explain the poorrepeatability of experimental results in these regions.

     

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