The Reynolds-Averaged Navier-Stokes (RANS) method is conducted to simulate flow around airfoil at high AOA. The separation is well captured using two-equation shear stress transport (SST/k-?) turbulence model accounting for turbulence motions. Calculation shows that the wing separation vortices are stable in several equilibrium stats, with the wing thickness up to a certain criteria, and AOA in a certain range. Meanwhile the separation transfers from one stable state to anther when certain disturbance is intruded. Comparing different disturbances, the translation is inclined to happen under heaving-pitching motions rather than forward-afterward vibrations. That is the exact one of most important reasons for aerodynamic loads data variation of airfoil at high AOA in wind tunnel test.%基于k-ω的SST两方程湍流模型,在时间域求解雷诺平均Navier-Stokes方程(RANS)计算了翼型大迎角分离流动.通过给翼型施加不同形式的扰动,重点关注了不同扰动形式对翼型大迎角分离涡流场平衡态的影响.研究表明:在所给定的百万雷诺数条件下,当翼型厚度达到一定程度而且在一定迎角范围内时,翼型的分离涡流场存在多个平衡态,且在一定扰动条件下会发生平衡态转移现象.在不同振动形式上,沉浮和俯仰比前后振动更易激发平衡态的转移.正是这种分离涡流场平衡态的多值现象,可能引发风洞实验中大迎角气动力数据的分散.
展开▼
