人－椅系统的动压计算问题

通过大量的分析、计算，提出了作用在人－椅系统上的动压修正系数F的半经验公式。给出选取修正因子ε、f（ε）的方法，仅需４个不同马赫数的阻力系数实验值。原则上，若实验结果精度较高，对阻力系数实验值的选取并无限制。但实验数据精度不高，则上述计算的阻力系数的均方根误差就会大些。此方法不仅适用于计算像人－椅系统这样的大钝体，而且也适用于计算其它大钝体在任意马赫数范围的阻力系数，其均方根误差小于01 05。

THE CALCULATION PROBLEM OF DYNAMIC PRESSURE ON AIRCREWMAN EJECTION SEAT SYSTEM

A new method of calculation that reflects actual situation of the dynamic pressure encountered by seat-man system, particularly at supersonic speeds is presented. Bason on large scale analyses and calculations, a semi-empirical mathematic expression of correction coefficient K of dynamic pressure exerting on seat-man systems is presented and the methods of selecting ε and f (ε) are proposed. For selecting ε and f (ε), only experimental data of drag coefficient at four different Mach numbers are needed. As a principle, the selection of experimental values of drag coefficients is free when the experimental values are of high precision, otherwise its root-mean-square error might be considerable. The present method is not only applicable for the calculation of drag coefficient of large blunt bodies such as seat-man system within arbitrary Mach number range, but also good for other large blunt bodies as well, and its root-mean-square error is less than 0 05. In addition, when the experimental values are expressed as semi-empirical mathematical equation it is convenient for computer programming or simulation under other situations.