中文摘要：

通过对头部无扰动和有扰动的两个细长体模型进行数值计算，分析了各个流场中涡系结构和气动力变化历程，并对比两者之间的差别。发现在高频率小振幅的俯仰振荡作用下，头部无扰动和有扰动的细长体的流场随时间的发展慢慢由非对称转变为对称。相对于头部有扰动的细长体，在第一个振荡周期内非定常俯仰运动对头部无扰动的细长体作用更明显。

英文摘要：

Computations are performed to simulate a slender body without disturbance flow flied and a slender body with nose-disturbed flow flied. By analyzing the vortex structure of flow field and aerodynamic force, it is showed that both of flow field gradually change from asymmetry to symmetry under the high frequency of small amplitude pitching oscillation. Pitching motion has more effect on flow field around the slender body without disturbance compared with the slender body with nose-disturbed in the first period.