机身后体装置对阻力的影响

1.引言 切尾运输机的机身后体阻力在总阻力中所占的比例仅次于表面摩阻及诱导阻力。机身后体附近的绕流不仅影响飞机的阻力,而且对空中投放及空中加油也有很大的影响。过去的研究得出底部附加隔板(减阻片)可起到减阻作用。现除了对减阻片的几何尺寸和安装位置需进行优化外,还需探索平尾上附加隔板以及后体台阶的减阻效果,以扩展减阻方案。

THE EFFECT OF AFTERBODY DEVICES ON DRAG REDUCTION

The effect of three kinds of devices, the base drag reducing plate, drag reducing strakes on tail and afterbody “terraces”, on drag reduction are experimentally invcstigated. Series of experiments are completed for selecting the geometric parameters and setting locations. The efficiencies are compared for different drag reduction devices. The results show that the base drag reducing plate is a simple and effective afterbody device of drag reduction. At α - 0, one of the base drag reducing plate, which has L = 0.8D and compatible setting locations, results in drag reduction 0.027 for body alone, with the relative value about 10.9% of body drag, and results in drag reduction 0.018 for configuration of body and tail, with relative value about 5.7%. The drag reducing strakes on tail also decrease drag, while afterbody“terraces”results in an increase of drag.