振动翼型和襟翼的绕流特性研究

用数值模拟手段详细地研究了振动翼型和襟翼的绕流问题,数值模拟的出发方程为Euler和N-S方程,格式为Bcam-Warming格式的改进型。数值实验主要针对流场的二大特性进行的,即振动对激波的影响和振动对分离的抑制作用,结果表明:(1)随翼型或襟翼的振动激波强度和位置也相应地变化但这一变化滞后于攻角的变化;(2)振幅加大激波强度的变化和激波运动范围也加大;(3)振动频率越高对激波的影响反而较低频时要小;(4)流动条件的不同可使升力回线的走向发生变化;(5)振动对分离有明显的抑制作用。

THE STUDY OF FLOW OVER OSCILLATING AIRFOILS AND AIRFOILS WITH TRAILING-EDGE FLAP

The dynamic precess was numerically simulated on a two dimensional oscillating airfoil or an airfoil with trailing-edge flap in pitch. The Euler and Navier-Stokes equations with Baldwin-Lomax turbulent model were required to solve using the implicit fac-torized finite difference algorithm(LU-AD1 algorithm), which was constructed n a body fitted coordinate system. The study was focused on the unsteady effect of shock wave and control of separation on the lifting surface due to the oscillation. The numerical results have shown that; (1) with the oscillation of the airfoil or trailing-edge flap the shock wave strength and its location are nonlinear response to the morion of lifting surface; (2) the larger the amplitude of oscillation, the more seriously the strength of the shock wave and its location vary; (3) the higher the reduced frequence, the less its influence on variable pressure jump; (4) the characteristics of lift force loop is determined by viscous effect; (5) the oscillating motion can control the separation and augment the lift force.