通过求解雷诺平均Navier-Stokes方程,研究了翼型在强迫振动和自然结构振动下的大迎角流场特性,尤其是失速迎角附近的流场和气动特性。研究结果表明:在接近颤振临界速度情况下结构自然振动可以引起翼型大尺度的分离,导致失速分离涡提前出现;强迫性的沉浮运动和俯仰运动在一定幅度下也可以引起失速性质的大分离,而且沉浮和俯仰振动的频率和振幅都是影响翼型大尺度分离的重要因素。
Based on the unsteady Reynolds-averaged Navier-Stokes equations, the flow field and aerodynamic characteristics of an airfoil at high incidences is investigated under the elastic structure vibration and different forced vibrations. It is shown that the aeroelastic vibration with certain amplitude near the critical flutter speed can cause large scale separation above the airfoil before the stall incidence, then, lead to the stall appearing at some lower incidence than the steady meaning stall incidence. Furthermore, the influences of three forced vibrations of the airfoil on the flow field at high incidences are considered. It is found that the forced plunging or pitching vibrations can also cause the large scale separation if the amplitudes of vibrations are large enough. The frequency and amplitude of the vibrations are important parameters.