论文部分内容阅读
采用一种基于k-ωSST模型和γ-θ转捩模型的雷诺平均N-S方程数值方法,对雷诺数Re=1.35×105下的NACA0012振荡翼型和静态翼型非定常流场和升力特性进行模拟,在缩减频率K=0.1的条件下研究了翼型振荡运动中平均攻角和振幅对平均升力系数的影响,并与静态翼型的升力特性及实验结果进行了对比。结果表明:当平均攻角小于临界攻角时,翼型的振荡运动会降低平均升力系数,当平均攻角大于临界攻角同时最小攻角小于临界攻角时,翼型的振荡可以提高平均升力系数。在平均攻角为12°~17°时,翼型振幅为6°左右时可获得最大平均升力系数,与静态翼型相比,平均升力系数可提高30%~45.7%。当振荡过程中最小攻角对应静态翼型轻失速攻角时,翼型上仰阶段前缘涡的产生和集中涡的稳定附着是平均升力系数大幅度阶跃式提升的原因,静态翼型与振荡翼型的组合可提高升力并拓宽攻角范围。
The unsteady flow field and lift characteristics of NACA0012 oscillating airfoil and static airfoil under Reynolds number Re = 1.35 × 105 are simulated by a Reynolds-averaged Navier-Stokes equations based on k-ωSST model and γ-θ transition model. The effect of average angle of attack and amplitude on the average lift coefficient was studied under the condition of reduced frequency K = 0.1 and compared with that of the static airfoil. The results show that when the average angle of attack is smaller than the critical angle of attack, the airfoil oscillation will reduce the average lift coefficient. When the average angle of attack is larger than the critical angle of attack and the minimum angle of attack is smaller than the critical angle of attack, the airfoil oscillation can increase the average lift coefficient . When the average angle of attack is 12 ° ~ 17 °, the maximum average lift coefficient is obtained when the airfoil amplitude is about 6 °, and the average lift coefficient can be increased by 30% ~ 45.7% compared with the static airfoil. When the minimum angle of attack corresponds to the angle of attack of static airfoil at light loss, the generation of leading edge vortex and the stable attachment of concentrated vortex are the reason for the step-up of average lift coefficient. The static airfoil and The combination of oscillating airfoils increases lift and widens the range of angles of attack.