多段翼型优化设计计算

 目标函数计算失真和选择合适的间接目标函数以减少机时是多段翼型优化计算要解决的关键问题。通过大量分析计算,对上述问题提出了下述解决办法:限制汇流强度使翼段间缝隙不过分狭窄,以解决目标函数计算失真问题。前缘缝翼优化时,用主翼面上的分离点位置作为间接目标函数;对后缘襟翼则分别以翼型升力值和分离点位置作为间接目标函数,进行优化计算。在间接目标函数优化的基础上再用最大升力系数为目标函数作少量验算即可获得可信的优化结果。实践证明这样可节省大量机时。

OPTIMUM DESIGN CALCULATION OF MULTIELEMENT AIRFOILS

The key problems on multi-element airfoils optimized for maximum lift arethe false calculation of the target function and how to select the suitable indirect target function to greatly decrease the CPU time. Based on a great deal of calculation, the valid method is obtained as follows. The condition that the confluent boundary layer can not form too early is used to restrict the gap between airfoil elements not too small, thus solving the problem of false caculation. For the optimization of a leading-edge slot, the separating position of the main element is used as indirect target function for optimizing caculation; and for that of a trailing-edge flap, the lift of the airfoil or separating position at the key airfoil element is used. Then a few further caculation with a target of maximum lift coefficient are carried out. The reliable results can be obtained repidly.