超临界翼型的跨音速抖振特性

BUFFET CHARACTERISTICS OF SUPERCRITICALAIRFOIL AT TRANSONIC FLOW

以二维非定常N S方程为基本方程 ,计算跨音速翼型升力系数的时间历程 .根据升力系数的脉动量急剧上升的起始点确定抖振起始边界 .以超临界机翼DFVLR R2和传统翼型NACA0 0 12为研究对象 ,研究了两种翼型的抖振特性 .计算结果表明 ,在超临界翼型的设计马赫数附近 ,超临界翼型具有良好的抖振特性 .

The 2-D time-dependent compressible Navier-Stokes equations are adopted as the governing equations. The unsteady lift coefficients of airfoil are calculated by Navier-Stokes equations with the implicit LU-NND algorithm, Baldwin-Lomax turbulent model and C-type grids. The fluctuating values of lift coefficient are increased with the enlargement of incidence and Mach number. The buffet onset boundary is defined as the beginning point where the fluctuating values of aerodynamic coefficients are increased suddenly. The fluctuating values of aerodynamic coefficients expresses the buffet strength. The buffet characteristics of supercritical airfoil DFVLR-R2 and airfoil NACA0012 are investigated. The calculating results show that:in the design Mach number range of supercritical airfoil, there are larger buffet onset incidence and less buffet loads. When Mach number is larger than the design Mach number, the buffet onset incidence of supercritical airfoil decreases quickly and there are rather large buffet loads. In the convention airfoil NACA 0012, there are much less buffet onset incidence, larger buffet loads and separated range. [