中文摘要：

为分析变来流速度状态下的旋翼翼型气动特性,提出了利用翼型平移来模拟来流速度变化的数值方法.在此方法基础上,采用基于隐式LU-SGS（lower upper symmetric Gauss-Seidal）方法的非定常雷诺平均N-S（Navier-Stokes）（RANS）方程,模拟了SC1095旋翼翼型在定迎角-变来流速度及变迎角-变来流速度状态下的非定常气动特性.通过对比分析发现：翼型在变速度-定迎角状态下会表现出明显的非定常现象,产生了前缘分离涡,气动特性会出现明显的迟滞效应及波动现象,脉动速度越大,非定常效果越明显.并且基准速度越大,翼型气动特性的峰值越大;翼型迎角越大,非定常涡出现的也越早.考虑直升机旋翼翼型实际工作环境,在变速度-动态失速状态下,翼型最大迎角处的气动力会得到一定程度的削弱,在小迎角下的气动力得到一定程度的增强,且脉动速度越大,翼型的非定常特性也越强.

英文摘要：

In order to analyze the aerodynamic characteristics of airfoil under the condition of unsteady free stream velocity, the moving-embedded grid method was employed to simulate the fluctuating velocity. Based on this method, the URANS （unsteady Reynoldsaveraged Navier-Stokes） equations coupling with the implicit scheme of LU-SGS （lower-upper symmetric Gauss-Seidel） was used to simulate the unsteady aerodynamic characteristics of the SC1095 airfoil under the condition of steady angle of attack with unsteady free stream velocity and under the condition of unsteady angle of attack with unsteady free stream velocity. It was discovered by comparing the calculated results that the unsteady characteristics, including hysteresis phenomenon, fluctuation and leading edge vortex induced by the unsteady free stream velocity, were observed under these conditions, and the unsteady characteristics were more obvious as the fluctuating velocity increased. By comparing the characteristics of airfoil at different basic velocities, it was found that the peaks of aerodynamic force curves enlarged as the basic velocity increased, and the unsteady vortex formed more early when the angle of attack increased. Considering the actual work environment of helicopter rotor, the aerodynamic loads of airfoil under dynamic stall were weakened at the large angle of attack and enhanced at the small angle of attack under the unsteady free stream velocity condition.