内吹式襟翼环量控制翼型升力响应特性

传统尖尾缘翼型通过控制迎角，综合利用襟翼、缝翼来改变升力，升力对迎角变化的时间响应历程可以用Wagner函数来描述，而内吹式襟翼（IBF）主要通过控制分离来拓展最大升力，并在一定范围内通过调节射流强度改变驻点位置和环量来对升力进行有效控制，其升力随吹气动量变化的时间响应尺度是否与传统尖尾缘翼型相同还不是很清楚。本文主要研究内吹式襟翼升力响应过程，并将其与传统尖后缘翼型升力响应特性进行对比。首先通过某襟翼偏角为30°的双圆弧环量控制翼型对数值方法进行验证，再对某最大厚度为18%弦长的亚声速翼型内吹式襟翼定常吹气控制下的流场进行非定常数值模拟，并分析了其中的瞬态特征。结果表明内吹式襟翼环量控制翼型对激励响应的时间依赖特征与Wagner函数有很好的相互关系，并可以用该函数来描述。

Lift response characteristics of a circulation control airfoil with internally blown flap

The lift of traditional airfoil with sharp trailing edge, for which the time response course to angle of attack can be described by Wagner function, changes with angle of attack under the combined effects of the flap and slat; while for the airfoil with Internally Blown Flap (IBF), whose maximum lift is increased by means of the suppression of flow separation, the lift is effectively adjusted by the blowing jet, which can induce the change of the location of stagnation point and the airfoil circulation. Considering that it is not clear whether the time response characteristics of the lift of the airfoil with IBF are the same as those of traditional airfoils or not, this paper investigates the former in detail with the focus on the comparison between them. With the numerical method validated by the case of dual-radius circulation control airfoil with a flap deflection angle of 30°, the unsteady flow field around the subsonic airfoil with the ratio of maximum thickness to chord of 18% and IBF are numerically simulated under the effect of steady blowing and its transient features are also analyzed. The results imply that the time dependence characteristics of the lift response of the circulation control airfoil with IBF to blowing excitation have a correlation with Wagner function and can be described by using it.