一种近无激波机翼修型的工程设计方法

本文利用现有解全速势方程的一种分析方法和“虚拟气体”概念,提出一种近无激波机翼修型的工程设计方法。避免原“虚拟气体”设计方法中在超音速域内的推进,而采用部分穿透速度边界条件的办法来获得修型的效果。以实现接近于无激波机翼的绕流流场。算例结果表明这种工程设计方法使用灵活,效果良好。

AN ENGINEERING APPROACH FOR NEARLY SHOCK-FREE WING DESIGN

Aerodynamic efficiency needs to be increased at transonic cruising speed with the constraints of desirable aerodynamic performance also at lower speeds. Reduced drag is obtained by avoiding flows with strong shock waves on the wing. A methdd to systematically change given shapes in order to arrive at shock-free flows and therefore obtain reduced drag is the "Elliptic continuation" or "Fictitious gas"method. But up to date the second step of this method has been used successfully only in the form of ill-posed space-marching methods for swept wings with high aspect ratio and low swept angles. It has been already observed and understood; that aerodynamic efficiency is optimal not at shock-free conditions, but at somewhat higher Mach number and lift coefficients than those used for design. In the present paper, we use a reliable transonic analysis algorithm with an analytic fictitious gas model to develop a simplified version of the design method which does not aim 'oward finding exactly shock-free flows but such ones with possibly only weak shocks. In this method, we use the transpiration velocity boundary condition rather than the space-marching procedure to simulate the surface deformation. As shown in the numerical example this procedure yields almost shock-free configurations.