翼型大迎角振动对气动性能影响的实验研究与初步分析

Experiment investigation and principium analysis for vibration on aerodynamics of an model airfoil at larger incidence

通过在NF-3低速风洞专门研制的翼型模型及相应的俯仰和沉浮振动机构,选用NACA0012翼型进行大迎角下不同频率的振动实验,研究了模型振动平均状态下对其气动力特性的影响情况,并在N-S方程基础上对振动流场进行了初步分析。实验与计算研究的结果表明:在临近定常失速迎角的大迎角条件下,翼型的振动可以引起旋涡分离,导致翼型升力减小和失速迎角的提前。就所涉及的两种振动模式而言,俯仰振动的影响大于沉浮振动,所以,模型设计和加工时要特别注意加强机翼弦向的扭转刚度。

Using the equipments in NF-3 wind tunnel which are specially designed to do plunging and pitching movement,NACA0012 airfoil is chosen to test with larger incidences.Its aerodynamic characteristics is investigated and analysed.And based on the solution of unsteady Reynolds-Averaged Navier-Stokes equations,the flow field around airfoil at high incidences are investigated under consideration of vibrations for wind-tunnel models.It is shown that the vibrations of the airfoil can cause large scale unsteady separated vortex shedding before the stall incidence,therefore,lead to lift decreasing and the stall appearing at some lower incidence than the steady meaning stall incidence.Concerning these two vibration modes,the effects of airfoil＇s pitching is serious than that of plunging.So the chord stiffness should be stronger in the process of model＇s design.