外挂俯仰连接刚度对机翼颤振的影响

本文使用v-g法、Niblett法和模型风洞试验3种方法,分析了机翼和外挂间俯仰连接刚度对机翼颤振的影响。并提出了“气动压力中心线”概念。用振型节线与压力中心线相对位置的变化,解释机翼/外挂颤振类型变化的机理。

EFFECTS OF THE PYLON PITCHING STIFFNESS ON WING-STORE FLUTTER

In the present paper, three methods i. e., v-g method, Niblett' s method and model wind-tunnel test, are used to analyze the effects of the pylon pitching stiffness on wing-store flutter, Niblett's method of the binary airfoil is extended to three-dimensional wing. The concept of the centre line of aerodynamic pressure is suggested, which is a line between aerodynamic centres of streamwise strip calculated by the horse-shoe vortex met od. The alteration of the re'ative position between the mode node-line and the centre line of aerodynamic pressure makes clear why the type of wing-store flutter changes and the flutter speed drops sharply .When the node-line of the store pitching dominant mode alters from the upstream side ahead of the centre line of aerodynamic pressure to the downstream side behind it, this makes the mode couple with the wing bending dominant mode, and results in the occurrence of flutter. And because the frequencies of the two modes are in proximity, the flutter speed is quite slow. So preliminary judgement of the occurrence of critical flutter mode transition can be got by using only the information about change of the natural modes.