Flow separation was observed on the expansion ramp at Mach 2.5.To improve off-design performance of single expansion ramp nozzles,variable geometry nozzle configuration should be adopted.

• 在马赫数2.；5时；喷管膨胀面气流已发生明显分离；喷管性能急剧恶化。 为了提高低马赫数条件下单膨胀斜面喷管的性能；采用变几何结构(调节下斜板角度)或基于二次流控制的单膨胀斜面喷管是必须的。