不变化的

Stepped is a weak form; swam and swum are strong.

Stepped 按规则变化的形，swam swum 不按规则变化的形。

The results show that the unstart boundary of supersonic inlets is mainly concerned with Mach number of freestream without considering the variation of angle of attack.

在不考虑攻角变化的条件下，进气道不起边界主要与来流马赫数有关。