中文摘要：

在亚临界流动范围内,利用DES方法对俯仰细长旋成体的流动特性进行数值模拟,给出了细长旋成体在大攻角纵向俯仰中的截面流态特点。研究发现,迎角变化跨越对称至不对称流态的上仰运动会产生明显的气动力迟滞现象,推迟了非对称的产生迎角,并延缓了细长体背风面流态之间的过渡。对细长体大攻角运动气动分析在国内外研究尚少,研究成果对充分利用非定常气动力有指导意义。

英文摘要：

Numerical investigations of flow behavior for pitching-up and pitching-down slender body are performed in subcritical Reynolds number region.Sectional slow pattern is observed and corresponding flow mechanism is analyzed.It is found that the obvious aerodynamic hysteresis will arise when the pitching oscillation of the model goes through the different flow condition（symmetric and asymmetric vortices）.Pitching motion delays the occurring angle of asymmetry and slows the transition of flowfield structure.Consequently the results are useful to the application of unsteady aerodynamic forces.