细长体截面绕流的稳定性及扰动的影响

应用拓扑结构的稳定性理论，分析了细长旋成体截面绕流的结构稳定性．在分析时取极限流线作为流场的内边界，并证明极限流线的鞍点-鞍点连接是拓扑结构稳定的A·D2通过分析发现，由于旋成体背涡的发展，导致截面流场拓扑结构变化，由稳定对称旋涡流态变成不稳定对称旋涡流态．此时流场中存在空间的鞍点-鞍点连接的不稳定拓扑结构，在小扰动下出现分叉，变成稳定非对称旋涡流态，形成非对称背涡．并应用开折理论分析了扰动对流场结构的影响．

Stability of the Crossflow Pattern Around a Slender and Influence of Disturbance

Topological structure and stability of a slender cross flow is discussed by the stability theory of dynamic system. The inner boundary of flow field was limiting streamline and it was proved that the topological structure connected saddles by limiting streamline is stable. It is proved that the development of slender vortices leads to the change of topological structure about cross flow. And it is the change from stable and symmetrical vortices flow pattern to unstable and symmetrical vortices flow pattern, and then to stable and asymmetrical vortices flow pattern due to little disturbance which leads to the development of asymmetrical slender vortices. The influence of disturbance to flowfield structure was discussed by unfolding theory too.