亚声速机翼快速摄动面元法

Rapid Perturbation Panel Method for Subsonic Wing

在内部Ｄｉｒｉｃｈｌｅｔ问题提法的面元法基础上，用解析法求几何外形摄动导数（偶强密度对机翼外形坐标的敏感性偏导数），从而快速确定机翼表面压力分布、升力系数和俯仰力矩系数。由于本文以偶强密度常值分布的低阶面无法为基础，故比以偶强密度二次分布的高阶面元法为基础的摄动面元法在最费机时的偏导数矩阵计算上要快一个量级，而由于以符合流场特性的物理内插代替加权几何内插，两者在确定物面压力分布时的准确度却基本一致。此外，本方法对内存要求较低，可处理较相应高阶方法更多的面元数。

A new and rapid analytic method based on the internal Diri-chlet boundary condition is presented for the calculation of aero-dynamic sensitivity derivativcs (doublet strength density with respect to each geometry coordinate)of multiple perturbations to a given baselinewing, and hence the pressure distribution, lift and pitching momentcoefficients can be determined very rapidly. Because the present methodis based on a low-order panel method with constant doublet strengthdensity instead of high-order one with quadratic doublet distribution, thecomputing cost required for the generation of the partial derivative mat-rix which spends most of the total charges for CPU execution times isless than about l/20 the cost of high-order method. However, by usingaphysical interpolation being compatible with flow field characteristicsinstead of weighted geometry interpolation, the accuracy for determingsurface pressure distributioa of the present method is actually identicalwith that of high-order method. Moreover, the present method can handlemuch more panels due to less storage requirement than that of high-ordermethod.